diff --git a/.flake8 b/.flake8
index 3099ce275..8ebfe017f 100644
--- a/.flake8
+++ b/.flake8
@@ -164,14 +164,6 @@ exclude =
         components/ulp/esp32ulp_mapgen.py,
         components/wifi_provisioning/python/wifi_config_pb2.py,
         components/wifi_provisioning/python/wifi_constants_pb2.py,
-        docs/conf_common.py,
-        docs/en/conf.py,
-        docs/gen-dxd.py,
-        docs/gen-toolchain-links.py,
-        docs/gen-version-specific-includes.py,
-        docs/link-roles.py,
-        docs/local_util.py,
-        docs/zh_CN/conf.py,
         examples/peripherals/can/can_alert_and_recovery/example_test.py,
         examples/peripherals/can/can_network/example_test.py,
         examples/peripherals/can/can_self_test/example_test.py,
diff --git a/docs/conf_common.py b/docs/conf_common.py
index 964ec9e15..a2dd2b946 100644
--- a/docs/conf_common.py
+++ b/docs/conf_common.py
@@ -16,10 +16,9 @@
 
 from __future__ import print_function
 from __future__ import unicode_literals
-import sys, os
-import re
+import sys
+import os
 import subprocess
-import shlex
 
 # Note: If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
@@ -41,11 +40,13 @@ try:
 except KeyError:
     idf_path = os.path.realpath(os.path.join(os.path.dirname(__file__), '..'))
 
+
 def call_with_python(cmd):
     # using sys.executable ensures that the scripts are called with the same Python interpreter
     if os.system('{} {}'.format(sys.executable, cmd)) != 0:
         raise RuntimeError('{} failed'.format(cmd))
 
+
 # Call Doxygen to get XML files from the header files
 print("Calling Doxygen to generate latest XML files")
 if os.system("doxygen ../Doxyfile") != 0:
@@ -58,6 +59,7 @@ copy_if_modified('xml/', 'xml_in/')
 # Generate 'api_name.inc' files using the XML files by Doxygen
 call_with_python('../gen-dxd.py')
 
+
 def find_component_files(parent_dir, target_filename):
     parent_dir = os.path.abspath(parent_dir)
     result = []
@@ -73,6 +75,7 @@ def find_component_files(parent_dir, target_filename):
     print("List of %s: %s" % (target_filename, ", ".join(result)))
     return result
 
+
 # Generate 'kconfig.inc' file from components' Kconfig files
 print("Generating kconfig.inc from kconfig contents")
 kconfig_inc_path = '{}/inc/kconfig.inc'.format(builddir)
@@ -90,7 +93,7 @@ confgen_args = [sys.executable,
                 "--env", "COMPONENT_KCONFIGS_PROJBUILD={}".format(" ".join(kconfig_projbuilds)),
                 "--env", "IDF_PATH={}".format(idf_path),
                 "--output", "docs", kconfig_inc_path + '.in'
-]
+                ]
 subprocess.check_call(confgen_args)
 copy_if_modified(kconfig_inc_path + '.in', kconfig_inc_path)
 
@@ -99,6 +102,7 @@ esp_err_inc_path = '{}/inc/esp_err_defs.inc'.format(builddir)
 call_with_python('../../tools/gen_esp_err_to_name.py --rst_output ' + esp_err_inc_path + '.in')
 copy_if_modified(esp_err_inc_path + '.in', esp_err_inc_path)
 
+
 # Generate version-related includes
 #
 # (Note: this is in a function as it needs to access configuration to get the language)
@@ -108,6 +112,7 @@ def generate_version_specific_includes(app):
     call_with_python('../gen-version-specific-includes.py {} {}'.format(app.config.language, version_tmpdir))
     copy_if_modified(version_tmpdir, '{}/inc'.format(builddir))
 
+
 # Generate toolchain download links
 print("Generating toolchain download links")
 base_url = 'https://dl.espressif.com/dl/'
@@ -116,26 +121,27 @@ call_with_python('../gen-toolchain-links.py ../../tools/toolchain_versions.mk {}
 copy_if_modified(toolchain_tmpdir, '{}/inc'.format(builddir))
 
 # http://stackoverflow.com/questions/12772927/specifying-an-online-image-in-sphinx-restructuredtext-format
-# 
+#
 suppress_warnings = ['image.nonlocal_uri']
 
 # -- General configuration ------------------------------------------------
 
+
 # If your documentation needs a minimal Sphinx version, state it here.
-#needs_sphinx = '1.0'
+# needs_sphinx = '1.0'
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = ['breathe',
-                   'link-roles',
-                   'sphinxcontrib.blockdiag',
-                   'sphinxcontrib.seqdiag',
-                   'sphinxcontrib.actdiag',
-                   'sphinxcontrib.nwdiag',
-                   'sphinxcontrib.rackdiag',
-                   'sphinxcontrib.packetdiag'
-                  ]
+              'link-roles',
+              'sphinxcontrib.blockdiag',
+              'sphinxcontrib.seqdiag',
+              'sphinxcontrib.actdiag',
+              'sphinxcontrib.nwdiag',
+              'sphinxcontrib.rackdiag',
+              'sphinxcontrib.packetdiag'
+              ]
 
 # Set up font for blockdiag, nwdiag, rackdiag and packetdiag
 blockdiag_fontpath = '../_static/DejaVuSans.ttf'
@@ -153,7 +159,7 @@ seqdiag_antialias = True
 # Doxygen regenerates files in 'xml/' directory every time,
 # but we copy files to 'xml_in/' only when they change, to speed up
 # incremental builds.
-breathe_projects = { "esp32-idf": "xml_in/" }
+breathe_projects = {"esp32-idf": "xml_in/"}
 breathe_default_project = "esp32-idf"
 
 # Add any paths that contain templates here, relative to this directory.
@@ -162,12 +168,11 @@ templates_path = ['_templates']
 # The suffix of source filenames.
 source_suffix = ['.rst', '.md']
 
-source_parsers = {
-       '.md': 'recommonmark.parser.CommonMarkParser',
-    }
+source_parsers = {'.md': 'recommonmark.parser.CommonMarkParser',
+                  }
 
 # The encoding of source files.
-#source_encoding = 'utf-8-sig'
+# source_encoding = 'utf-8-sig'
 
 # The master toctree document.
 master_doc = 'index'
@@ -192,9 +197,9 @@ print('Version: {0}  Release: {1}'.format(version, release))
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
-#today = ''
+# today = ''
 # Else, today_fmt is used as the format for a strftime call.
-#today_fmt = '%B %d, %Y'
+# today_fmt = '%B %d, %Y'
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
@@ -202,27 +207,27 @@ exclude_patterns = ['_build','README.md']
 
 # The reST default role (used for this markup: `text`) to use for all
 # documents.
-#default_role = None
+# default_role = None
 
 # If true, '()' will be appended to :func: etc. cross-reference text.
-#add_function_parentheses = True
+# add_function_parentheses = True
 
 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
-#add_module_names = True
+# add_module_names = True
 
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
-#show_authors = False
+# show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'
 
 # A list of ignored prefixes for module index sorting.
-#modindex_common_prefix = []
+# modindex_common_prefix = []
 
 # If true, keep warnings as "system message" paragraphs in the built documents.
-#keep_warnings = False
+# keep_warnings = False
 
 
 # -- Options for HTML output ----------------------------------------------
@@ -234,17 +239,17 @@ html_theme = 'sphinx_rtd_theme'
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-#html_theme_options = {}
+# html_theme_options = {}
 
 # Add any paths that contain custom themes here, relative to this directory.
-#html_theme_path = []
+# html_theme_path = []
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-#html_title = None
+# html_title = None
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
-#html_short_title = None
+# html_short_title = None
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
@@ -253,7 +258,7 @@ html_logo = "../_static/espressif-logo.svg"
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.
-#html_favicon = None
+# html_favicon = None
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
@@ -263,48 +268,48 @@ html_static_path = ['../_static']
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied
 # directly to the root of the documentation.
-#html_extra_path = []
+# html_extra_path = []
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-#html_last_updated_fmt = '%b %d, %Y'
+# html_last_updated_fmt = '%b %d, %Y'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
-#html_use_smartypants = True
+# html_use_smartypants = True
 
 # Custom sidebar templates, maps document names to template names.
-#html_sidebars = {}
+# html_sidebars = {}
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-#html_additional_pages = {}
+# html_additional_pages = {}
 
 # If false, no module index is generated.
-#html_domain_indices = True
+# html_domain_indices = True
 
 # If false, no index is generated.
-#html_use_index = True
+# html_use_index = True
 
 # If true, the index is split into individual pages for each letter.
-#html_split_index = False
+# html_split_index = False
 
 # If true, links to the reST sources are added to the pages.
-#html_show_sourcelink = True
+# html_show_sourcelink = True
 
 # If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
-#html_show_sphinx = True
+# html_show_sphinx = True
 
 # If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-#html_show_copyright = True
+# html_show_copyright = True
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-#html_use_opensearch = ''
+# html_use_opensearch = ''
 
 # This is the file name suffix for HTML files (e.g. ".xhtml").
-#html_file_suffix = None
+# html_file_suffix = None
 
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'ReadtheDocsTemplatedoc'
@@ -313,43 +318,43 @@ htmlhelp_basename = 'ReadtheDocsTemplatedoc'
 # -- Options for LaTeX output ---------------------------------------------
 
 latex_elements = {
-# The paper size ('letterpaper' or 'a4paper').
-#'papersize': 'letterpaper',
-
-# The font size ('10pt', '11pt' or '12pt').
-#'pointsize': '10pt',
-
-# Additional stuff for the LaTeX preamble.
-#'preamble': '',
+    # The paper size ('letterpaper' or 'a4paper').
+    # 'papersize': 'letterpaper',
+    #
+    # The font size ('10pt', '11pt' or '12pt').
+    # 'pointsize': '10pt',
+    #
+    # Additional stuff for the LaTeX preamble.
+    # 'preamble': '',
 }
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-  ('index', 'ReadtheDocsTemplate.tex', u'Read the Docs Template Documentation',
-   u'Read the Docs', 'manual'),
+    ('index', 'ReadtheDocsTemplate.tex', u'Read the Docs Template Documentation',
+     u'Read the Docs', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
-#latex_logo = None
+# latex_logo = None
 
 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
-#latex_use_parts = False
+# latex_use_parts = False
 
 # If true, show page references after internal links.
-#latex_show_pagerefs = False
+# latex_show_pagerefs = False
 
 # If true, show URL addresses after external links.
-#latex_show_urls = False
+# latex_show_urls = False
 
 # Documents to append as an appendix to all manuals.
-#latex_appendices = []
+# latex_appendices = []
 
 # If false, no module index is generated.
-#latex_domain_indices = True
+# latex_domain_indices = True
 
 
 # -- Options for manual page output ---------------------------------------
@@ -362,7 +367,7 @@ man_pages = [
 ]
 
 # If true, show URL addresses after external links.
-#man_show_urls = False
+# man_show_urls = False
 
 
 # -- Options for Texinfo output -------------------------------------------
@@ -371,22 +376,23 @@ man_pages = [
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-  ('index', 'ReadtheDocsTemplate', u'Read the Docs Template Documentation',
-   u'Read the Docs', 'ReadtheDocsTemplate', 'One line description of project.',
-   'Miscellaneous'),
+    ('index', 'ReadtheDocsTemplate', u'Read the Docs Template Documentation',
+     u'Read the Docs', 'ReadtheDocsTemplate', 'One line description of project.',
+     'Miscellaneous'),
 ]
 
 # Documents to append as an appendix to all manuals.
-#texinfo_appendices = []
+# texinfo_appendices = []
 
 # If false, no module index is generated.
-#texinfo_domain_indices = True
+# texinfo_domain_indices = True
 
 # How to display URL addresses: 'footnote', 'no', or 'inline'.
-#texinfo_show_urls = 'footnote'
+# texinfo_show_urls = 'footnote'
 
 # If true, do not generate a @detailmenu in the "Top" node's menu.
-#texinfo_no_detailmenu = False
+# texinfo_no_detailmenu = False
+
 
 # Override RTD CSS theme to introduce the theme corrections
 # https://github.com/rtfd/sphinx_rtd_theme/pull/432
diff --git a/docs/en/conf.py b/docs/en/conf.py
index a7dde4b1d..6c587bdf7 100644
--- a/docs/en/conf.py
+++ b/docs/en/conf.py
@@ -6,9 +6,10 @@
 
 # Importing conf_common adds all the non-language-specific
 # parts to this conf module
-import sys, os
+import sys
+import os
 sys.path.insert(0, os.path.abspath('..'))
-from conf_common import *
+from conf_common import *  # noqa: F401, F403 - need to make available everything from common
 
 # General information about the project.
 project = u'ESP-IDF Programming Guide'
diff --git a/docs/gen-dxd.py b/docs/gen-dxd.py
index ee2c692c1..2a6b9ba40 100755
--- a/docs/gen-dxd.py
+++ b/docs/gen-dxd.py
@@ -41,7 +41,7 @@ all_kinds = [
     ("define", "Macros"),
     ("typedef", "Type Definitions"),
     ("enum", "Enumerations")
-    ]
+]
 """list of items that will be generated for a single API file
 """
 
@@ -78,7 +78,7 @@ def get_doxyfile_input():
         # process only lines that are not comments
         if line.find("#") == -1:
             # extract header file path inside components folder
-            m = re.search(header_file_path_prefix + "(.*\.h)", line)
+            m = re.search(header_file_path_prefix + "(.*\.h)", line)  # noqa: W605 - regular expression
             header_file_path = m.group(1)
             doxyfile_INPUT += header_file_path + "\n"
         # proceed reading next line
diff --git a/docs/gen-toolchain-links.py b/docs/gen-toolchain-links.py
index aa824b93c..ea90f47c7 100644
--- a/docs/gen-toolchain-links.py
+++ b/docs/gen-toolchain-links.py
@@ -10,6 +10,7 @@ from __future__ import print_function
 import sys
 import os
 
+
 def main():
     if len(sys.argv) != 4:
         print("Usage: gen-toolchain-links.py <versions file> <base download URL> <output directory>")
@@ -48,10 +49,10 @@ def main():
     ./bootstrap && ./configure --enable-local && make install
 """
 
-    platform_info = [ ["linux64", "tar.gz", "z", unpack_code_linux_macos],
-                      ["linux32", "tar.gz", "z", unpack_code_linux_macos],
-                      ["osx", "tar.gz", "z", unpack_code_linux_macos],
-                      ["win32", "zip", None, None]]
+    platform_info = [["linux64", "tar.gz", "z", unpack_code_linux_macos],
+                     ["linux32", "tar.gz", "z", unpack_code_linux_macos],
+                     ["osx", "tar.gz", "z", unpack_code_linux_macos],
+                     ["win32", "zip", None, None]]
 
     with open(os.path.join(out_dir, 'download-links.inc'), "w") as links_file:
         for p in platform_info:
@@ -61,8 +62,8 @@ def main():
             unpack_code = p[3]
 
             archive_name = 'xtensa-esp32-elf-{}-{}-{}.{}'.format(
-                    platform_name, toolchain_desc, gcc_version, extension)
-            
+                platform_name, toolchain_desc, gcc_version, extension)
+
             print('.. |download_link_{}| replace:: {}{}'.format(
                 platform_name, base_url, archive_name), file=links_file)
 
@@ -73,5 +74,6 @@ def main():
     with open(os.path.join(out_dir, 'scratch-build-code.inc'), "w") as code_file:
         print(scratch_build_code_linux_macos, file=code_file)
 
+
 if __name__ == "__main__":
     main()
diff --git a/docs/gen-version-specific-includes.py b/docs/gen-version-specific-includes.py
index fd2264073..42051213c 100755
--- a/docs/gen-version-specific-includes.py
+++ b/docs/gen-version-specific-includes.py
@@ -13,9 +13,9 @@ import sys
 import re
 
 TEMPLATES = {
-    "en" : {
-        "git-clone" : {
-            "template" : """
+    "en": {
+        "git-clone": {
+            "template": """
 To obtain a local copy: open terminal, navigate to the directory you want to put ESP-IDF, and clone the repository using ``git clone`` command::
 
     cd ~/esp
@@ -30,32 +30,37 @@ ESP-IDF will be downloaded into ``~/esp/esp-idf``.
 .. note::
 
     %(zipfile_note)s
-"""
-            ,"master" : 'This command will clone the master branch, which has the latest development ("bleeding edge") version of ESP-IDF. It is fully functional and updated on weekly basis with the most recent features and bugfixes.'
-            ,"branch" : 'The ``git clone`` option ``-b %(clone_arg)s`` tells git to clone the %(ver_type)s in the ESP-IDF repository corresponding to this version of the documentation.'
-            ,"zipfile" : {
-                "stable" : 'As a fallback, it is also possible to download a zip file of this stable release from the `Releases page`_. Do not download the "Source code" zip file(s) generated automatically by GitHub, they do not work with ESP-IDF.'
-                ,"unstable" : 'GitHub\'s "Download zip file" feature does not work with ESP-IDF, a ``git clone`` is required. As a fallback, `Stable version`_ can be installed without Git.'
-                },  # zipfile
-            },  # git-clone
-        "version-note" : {
-            "master" : """
+""",
+            "master": 'This command will clone the master branch, which has the latest development ("bleeding edge") '
+                      'version of ESP-IDF. It is fully functional and updated on weekly basis with the most recent features and bugfixes.',
+            "branch": 'The ``git clone`` option ``-b %(clone_arg)s`` tells git to clone the %(ver_type)s in the ESP-IDF repository '
+                      'corresponding to this version of the documentation.',
+            "zipfile": {
+                "stable": 'As a fallback, it is also possible to download a zip file of this stable release from the `Releases page`_. '
+                          'Do not download the "Source code" zip file(s) generated automatically by GitHub, they do not work with ESP-IDF.',
+                "unstable": 'GitHub\'s "Download zip file" feature does not work with ESP-IDF, a ``git clone`` is required. As a fallback, '
+                            '`Stable version`_ can be installed without Git.'
+            },  # zipfile
+        },  # git-clone
+        "version-note": {
+            "master": """
 .. note::
-     This is documentation for the master branch (latest version) of ESP-IDF. This version is under continual development. `Stable version`_ documentation is available, as well as other :doc:`/versions`.
-"""
-            ,"stable" : """
+     This is documentation for the master branch (latest version) of ESP-IDF. This version is under continual development.
+     `Stable version`_ documentation is available, as well as other :doc:`/versions`.
+""",
+            "stable": """
 .. note::
      This is documentation for stable version %s of ESP-IDF. Other :doc:`/versions` are also available.
-"""
-            ,"branch" : """
+""",
+            "branch": """
 .. note::
      This is documentation for %s ``%s`` of ESP-IDF. Other :doc:`/versions` are also available.
 """
-            },  # version-note
-    }, # en
-    "zh_CN" : {
-        "git-clone" : {
-            "template" : """
+        },  # version-note
+    },  # en
+    "zh_CN": {
+        "git-clone": {
+            "template": """
 获取本地副本：打开终端，切换到你要存放 ESP-IDF 的工作目录，使用 ``git clone`` 命令克隆远程仓库::
 
     cd ~/esp
@@ -70,30 +75,32 @@ ESP-IDF 将会被下载到 ``~/esp/esp-idf`` 目录下。
 .. note::
 
     %(zipfile_note)s
-"""
-            ,"master" : '此命令将克隆 master 分支，该分支保存着 ESP-IDF 的最新版本，它功能齐全，每周都会更新一些新功能并修正一些错误。'
-            ,"branch" : '``git clone`` 命令的 ``-b %(clone_arg)s`` 选项告诉 git 从 ESP-IDF 仓库中克隆与此版本的文档对应的分支。'
-            ,"zipfile" : {
-                "stable" : '作为备份，还可以从 `Releases page`_ 下载此稳定版本的 zip 文件。不要下载由 GitHub 自动生成的"源代码"的 zip 文件，它们不适用于 ESP-IDF。'
-                ,"unstable" : 'GitHub 中"下载 zip 文档"的功能不适用于 ESP-IDF，所以需要使用 ``git clone`` 命令。作为备份，可以在没有安装 Git 的环境中下载 `Stable version`_ 的 zip 归档文件。'
-                },  # zipfile
-            },  # git-clone
-        "version-note" : {
-            "master" : """
+""",
+            "master": '此命令将克隆 master 分支，该分支保存着 ESP-IDF 的最新版本，它功能齐全，每周都会更新一些新功能并修正一些错误。',
+            "branch": '``git clone`` 命令的 ``-b %(clone_arg)s`` 选项告诉 git 从 ESP-IDF 仓库中克隆与此版本的文档对应的分支。',
+            "zipfile": {
+                "stable": '作为备份，还可以从 `Releases page`_ 下载此稳定版本的 zip 文件。不要下载由 GitHub 自动生成的"源代码"的 zip 文件，它们不适用于 ESP-IDF。',
+                "unstable": 'GitHub 中"下载 zip 文档"的功能不适用于 ESP-IDF，所以需要使用 ``git clone`` 命令。作为备份，可以在没有安装 Git 的环境中下载 '
+                            '`Stable version`_ 的 zip 归档文件。'
+            },  # zipfile
+        },  # git-clone
+        "version-note": {
+            "master": """
 .. note::
      这是ESP-IDF master 分支（最新版本）的文档，该版本在持续开发中。还有 `Stable version`_ 的文档，以及其他版本的文档 :doc:`/versions` 供参考。
-     This is documentation for the master branch (latest version) of ESP-IDF. This version is under continual development. `Stable version`_ documentation is available, as well as other :doc:`/versions`.
-"""
-            ,"stable" : """
+     This is documentation for the master branch (latest version) of ESP-IDF. This version is under continual development. `Stable version`_ documentation is '
+     'available, as well as other :doc:`/versions`.
+""",
+            "stable": """
 .. note::
      这是ESP-IDF 稳定版本 %s 的文档，还有其他版本的文档 :doc:`/versions` 供参考。
-"""
-            ,"branch" : """
+""",
+            "branch": """
 .. note::
      这是ESP-IDF %s ``%s`` 版本的文档，还有其他版本的文档 :doc:`/versions` 供参考。
 """
-            },  # version-note
-    }# zh_CN
+        },  # version-note
+    }  # zh_CN
 }
 
 
@@ -121,15 +128,15 @@ def write_git_clone_inc(template, out_dir, version, ver_type, is_stable):
     zipfile = template["zipfile"]
     if version == "master":
         args = {
-            "clone_args" : "",
-            "extra_note" : template["master"],
-            "zipfile_note" : zipfile["unstable"]
+            "clone_args": "",
+            "extra_note": template["master"],
+            "zipfile_note": zipfile["unstable"]
         }
     else:
         args = {
-            "clone_args" : "-b %s " % version,
-            "extra_note" : template["branch"] % {"clone_arg" : version, "ver_type" : ver_type},
-            "zipfile_note" : zipfile["stable"] if is_stable else zipfile["unstable"]
+            "clone_args": "-b %s " % version,
+            "extra_note": template["branch"] % {"clone_arg": version, "ver_type": ver_type},
+            "zipfile_note": zipfile["stable"] if is_stable else zipfile["unstable"]
         }
     out_file = os.path.join(out_dir, "git-clone.inc")
     with open(out_file, "w", encoding='utf-8') as f:
@@ -172,7 +179,7 @@ def get_version():
     print("refs:\n%s" % refs)
     refs = refs.split(b"\n")
     # Note: this looks for branches in 'origin' because GitLab CI doesn't check out a local branch
-    branches = [ r.replace(b"refs/remotes/origin/",b"").strip() for r in refs if r.startswith(b"refs/remotes/origin/") ]
+    branches = [r.replace(b"refs/remotes/origin/",b"").strip() for r in refs if r.startswith(b"refs/remotes/origin/")]
     if len(branches) == 0:
         # last resort, return the commit (may happen on Gitlab CI sometimes, unclear why)
         return (subprocess.check_output(["git", "rev-parse", "--short", "HEAD"]).strip(), "commit", False)
@@ -181,5 +188,6 @@ def get_version():
     else:
         return (branches[0], "branch", False)  # take whatever the first branch is
 
+
 if __name__ == "__main__":
     main()
diff --git a/docs/link-roles.py b/docs/link-roles.py
index c24d2007f..e97eb2e6e 100644
--- a/docs/link-roles.py
+++ b/docs/link-roles.py
@@ -7,6 +7,7 @@ import os
 from docutils import nodes
 from local_util import run_cmd_get_output
 
+
 def get_github_rev():
     path = run_cmd_get_output('git rev-parse --short HEAD')
     tag = run_cmd_get_output('git describe --exact-match')
@@ -16,6 +17,7 @@ def get_github_rev():
         path = tag
     return path
 
+
 def setup(app):
     rev = get_github_rev()
 
@@ -39,14 +41,15 @@ def setup(app):
         if (run_cmd_get_output('git rev-parse --short HEAD') != rev):
             tag_rev = rev
     else:
-        # if not on the RTD then provide generic identification 
+        # if not on the RTD then provide generic identification
         tag_rev = run_cmd_get_output('git describe --always')
 
     app.add_role('link_to_translation', crosslink('%s../../%s/{}/%s.html'.format(tag_rev)))
 
+
 def autolink(pattern):
     def role(name, rawtext, text, lineno, inliner, options={}, content=[]):
-        m = re.search('(.*)\s*<(.*)>', text)
+        m = re.search('(.*)\s*<(.*)>', text)  # noqa: W605 - regular expression
         if m:
             link_text = m.group(1)
             link = m.group(2)
@@ -58,12 +61,13 @@ def autolink(pattern):
         return [node], []
     return role
 
+
 def crosslink(pattern):
     def role(name, rawtext, text, lineno, inliner, options={}, content=[]):
         (language, link_text) = text.split(':')
         docname = inliner.document.settings.env.docname
         doc_path = inliner.document.settings.env.doc2path(docname, None, None)
-        return_path = '../' * doc_path.count('/') 
+        return_path = '../' * doc_path.count('/')
         url = pattern % (return_path, language, docname)
         node = nodes.reference(rawtext, link_text, refuri=url, **options)
         return [node], []
diff --git a/docs/local_util.py b/docs/local_util.py
index 38b324bde..666afa953 100644
--- a/docs/local_util.py
+++ b/docs/local_util.py
@@ -16,13 +16,14 @@
 
 from __future__ import unicode_literals
 from io import open
-import re
 import os
 import shutil
 
+
 def run_cmd_get_output(cmd):
     return os.popen(cmd).read().strip()
 
+
 def files_equal(path_1, path_2):
     if not os.path.exists(path_1) or not os.path.exists(path_2):
         return False
@@ -34,6 +35,7 @@ def files_equal(path_1, path_2):
         file_2_contents = f_2.read()
     return file_1_contents == file_2_contents
 
+
 def copy_file_if_modified(src_file_path, dst_file_path):
     if not files_equal(src_file_path, dst_file_path):
         dst_dir_name = os.path.dirname(dst_file_path)
@@ -41,6 +43,7 @@ def copy_file_if_modified(src_file_path, dst_file_path):
             os.makedirs(dst_dir_name)
         shutil.copy(src_file_path, dst_file_path)
 
+
 def copy_if_modified(src_path, dst_path):
     if os.path.isfile(src_path):
         copy_file_if_modified(src_path, dst_path)
@@ -52,4 +55,3 @@ def copy_if_modified(src_path, dst_path):
             src_file_path = os.path.join(root, src_file_name)
             dst_file_path = os.path.join(dst_path + root[src_path_len:], src_file_name)
             copy_file_if_modified(src_file_path, dst_file_path)
-
diff --git a/docs/zh_CN/conf.py b/docs/zh_CN/conf.py
index a4017c8c0..ff747bf7e 100644
--- a/docs/zh_CN/conf.py
+++ b/docs/zh_CN/conf.py
@@ -6,9 +6,10 @@
 
 # Importing conf_common adds all the non-language-specific
 # parts to this conf module
-import sys, os
+import sys
+import os
 sys.path.insert(0, os.path.abspath('..'))
-from conf_common import *
+from conf_common import *  # noqa: F401, F403 - need to make available everything from common
 
 # General information about the project.
 project = u'ESP-IDF 编程指南'