chore: blacken (#375)

diff --git a/docs/conf.py b/docs/conf.py
index 2ac5f34..831c752 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -33,40 +33,40 @@
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    'sphinx.ext.autodoc',
-    'sphinx.ext.intersphinx',
-    'sphinx.ext.viewcode',
-    'sphinx.ext.napoleon',
-    'sphinx_docstring_typing'
+    "sphinx.ext.autodoc",
+    "sphinx.ext.intersphinx",
+    "sphinx.ext.viewcode",
+    "sphinx.ext.napoleon",
+    "sphinx_docstring_typing",
 ]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
 # source_suffix = ['.rst', '.md']
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
 #
 # source_encoding = 'utf-8-sig'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'google-auth'
-copyright = '2016, Google, Inc.'
-author = 'Google, Inc.'
+project = "google-auth"
+copyright = "2016, Google, Inc."
+author = "Google, Inc."
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = pkg_resources.get_distribution('google-auth').version
+version = pkg_resources.get_distribution("google-auth").version
 # The full version, including alpha/beta/rc tags.
 release = version
 
@@ -89,7 +89,7 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This patterns also effect to html_static_path and html_extra_path
-exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
 
 # The reST default role (used for this markup: `text`) to use for all
 # documents.
@@ -111,7 +111,7 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []
@@ -128,21 +128,21 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'alabaster'
+html_theme = "alabaster"
 
 # 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 = {
-    'description': 'Google Auth Library for Python',
-    'github_user': 'GoogleCloudPlatform',
-    'github_repo': 'google-auth-library-python',
-    'github_banner': True,
-    'travis_button': True,
-    'font_family': "'Roboto', Georgia, sans",
-    'head_font_family': "'Roboto', Georgia, serif",
-    'code_font_family': "'Roboto Mono', 'Consolas', monospace",
+    "description": "Google Auth Library for Python",
+    "github_user": "GoogleCloudPlatform",
+    "github_repo": "google-auth-library-python",
+    "github_banner": True,
+    "travis_button": True,
+    "font_family": "'Roboto', Georgia, sans",
+    "head_font_family": "'Roboto', Georgia, serif",
+    "code_font_family": "'Roboto Mono', 'Consolas', monospace",
 }
 
 # Add any paths that contain custom themes here, relative to this directory.
@@ -171,7 +171,7 @@
 # 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,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+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
@@ -194,12 +194,7 @@
 #
 
 html_sidebars = {
-    '**': [
-        'about.html',
-        'navigation.html',
-        'relations.html',
-        'searchbox.html',
-    ]
+    "**": ["about.html", "navigation.html", "relations.html", "searchbox.html"]
 }
 
 # Additional templates that should be rendered to pages, maps page names to
@@ -259,34 +254,36 @@
 # html_search_scorer = 'scorer.js'
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'google-authdoc'
+htmlhelp_basename = "google-authdoc"
 
 # -- 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': '',
-
-     # Latex figure (float) alignment
-     #
-     # 'figure_align': 'htbp',
+    # The paper size ('letterpaper' or 'a4paper').
+    #
+    # 'papersize': 'letterpaper',
+    # The font size ('10pt', '11pt' or '12pt').
+    #
+    # 'pointsize': '10pt',
+    # Additional stuff for the LaTeX preamble.
+    #
+    # 'preamble': '',
+    # Latex figure (float) alignment
+    #
+    # 'figure_align': 'htbp',
 }
 
 # 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 = [
-    (master_doc, 'google-auth.tex', 'google-auth Documentation',
-     'Google, Inc.', 'manual'),
+    (
+        master_doc,
+        "google-auth.tex",
+        "google-auth Documentation",
+        "Google, Inc.",
+        "manual",
+    )
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -326,10 +323,7 @@
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [
-    (master_doc, 'google-auth', 'google-auth Documentation',
-     [author], 1)
-]
+man_pages = [(master_doc, "google-auth", "google-auth Documentation", [author], 1)]
 
 # If true, show URL addresses after external links.
 #
@@ -342,9 +336,15 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    (master_doc, 'google-auth', 'google-auth Documentation',
-     author, 'google-auth', 'One line description of project.',
-     'Miscellaneous'),
+    (
+        master_doc,
+        "google-auth",
+        "google-auth Documentation",
+        author,
+        "google-auth",
+        "One line description of project.",
+        "Miscellaneous",
+    )
 ]
 
 # Documents to append as an appendix to all manuals.
@@ -366,14 +366,13 @@
 
 # Example configuration for intersphinx: refer to the Python standard library.
 intersphinx_mapping = {
-    'python': ('https://docs.python.org/3.5', None),
-    'urllib3': ('https://urllib3.readthedocs.io/en/stable', None),
-    'requests': ('http://docs.python-requests.org/en/stable', None),
-    'requests-oauthlib': (
-        'http://requests-oauthlib.readthedocs.io/en/stable', None),
+    "python": ("https://docs.python.org/3.5", None),
+    "urllib3": ("https://urllib3.readthedocs.io/en/stable", None),
+    "requests": ("http://docs.python-requests.org/en/stable", None),
+    "requests-oauthlib": ("http://requests-oauthlib.readthedocs.io/en/stable", None),
 }
 
 # Autodoc config
-autoclass_content = 'both'
-autodoc_member_order = 'bysource'
-autodoc_mock_imports = ['grpc']
+autoclass_content = "both"
+autodoc_member_order = "bysource"
+autodoc_mock_imports = ["grpc"]