diff --git a/src/pip/_internal/__init__.py b/src/pip/_internal/__init__.py
index 532edd26c85..fede520fad7 100755
--- a/src/pip/_internal/__init__.py
+++ b/src/pip/_internal/__init__.py
@@ -29,8 +29,8 @@
 except ImportError:
     pass
 else:
-    if (sys.platform == "darwin" and
-            ssl.OPENSSL_VERSION_NUMBER < 0x1000100f):  # OpenSSL 1.0.1
+    # Checks for OpenSSL 1.0.1 on MacOS
+    if sys.platform == "darwin" and ssl.OPENSSL_VERSION_NUMBER < 0x1000100f:
         try:
             from pip._vendor.urllib3.contrib import securetransport
         except (ImportError, OSError):
@@ -148,7 +148,8 @@ def create_main_parser():
 
     pip_pkg_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     parser.version = 'pip %s from %s (python %s)' % (
-        __version__, pip_pkg_dir, sys.version[:3])
+        __version__, pip_pkg_dir, sys.version[:3],
+    )
 
     # add the general options
     gen_opts = cmdoptions.make_option_group(cmdoptions.general_group, parser)
diff --git a/src/pip/_internal/cmdoptions.py b/src/pip/_internal/cmdoptions.py
index eaabdbde6fc..28d36fed6f9 100644
--- a/src/pip/_internal/cmdoptions.py
+++ b/src/pip/_internal/cmdoptions.py
@@ -56,7 +56,8 @@ def getname(n):
         fmt_ctl_no_binary(control)
         warnings.warn(
             'Disabling all use of wheels due to the use of --build-options '
-            '/ --global-options / --install-options.', stacklevel=2)
+            '/ --global-options / --install-options.', stacklevel=2,
+        )
 
 
 ###########
@@ -366,13 +367,15 @@ def _get_format_control(values, option):
 def _handle_no_binary(option, opt_str, value, parser):
     existing = getattr(parser.values, option.dest)
     fmt_ctl_handle_mutual_exclude(
-        value, existing.no_binary, existing.only_binary)
+        value, existing.no_binary, existing.only_binary,
+    )
 
 
 def _handle_only_binary(option, opt_str, value, parser):
     existing = getattr(parser.values, option.dest)
     fmt_ctl_handle_mutual_exclude(
-        value, existing.only_binary, existing.no_binary)
+        value, existing.only_binary, existing.no_binary,
+    )
 
 
 def no_binary():
diff --git a/src/pip/_internal/commands/check.py b/src/pip/_internal/commands/check.py
index ea7dc909439..945af705acb 100644
--- a/src/pip/_internal/commands/check.py
+++ b/src/pip/_internal/commands/check.py
@@ -22,14 +22,16 @@ def run(self, options, args):
             for requirement in missing_reqs_dict.get(dist.key, []):
                 logger.info(
                     "%s %s requires %s, which is not installed.",
-                    dist.project_name, dist.version, requirement.project_name)
+                    dist.project_name, dist.version, requirement.project_name,
+                )
 
             for requirement, actual in incompatible_reqs_dict.get(
                     dist.key, []):
                 logger.info(
                     "%s %s has requirement %s, but you have %s %s.",
                     dist.project_name, dist.version, requirement,
-                    actual.project_name, actual.version)
+                    actual.project_name, actual.version,
+                )
 
         if missing_reqs_dict or incompatible_reqs_dict:
             return 1
diff --git a/src/pip/_internal/commands/download.py b/src/pip/_internal/commands/download.py
index e64912e4173..f05f6447c2a 100644
--- a/src/pip/_internal/commands/download.py
+++ b/src/pip/_internal/commands/download.py
@@ -222,9 +222,7 @@ def run(self, options, args):
                     req.name for req in requirement_set.successfully_downloaded
                 ])
                 if downloaded:
-                    logger.info(
-                        'Successfully downloaded %s', downloaded
-                    )
+                    logger.info('Successfully downloaded %s', downloaded)
 
                 # Clean up
                 if not options.no_clean:
diff --git a/src/pip/_internal/commands/freeze.py b/src/pip/_internal/commands/freeze.py
index 2ac0bf9ca7e..5c0e339705d 100644
--- a/src/pip/_internal/commands/freeze.py
+++ b/src/pip/_internal/commands/freeze.py
@@ -86,7 +86,8 @@ def run(self, options, args):
             isolated=options.isolated_mode,
             wheel_cache=wheel_cache,
             skip=skip,
-            exclude_editable=options.exclude_editable)
+            exclude_editable=options.exclude_editable,
+        )
 
         for line in freeze(**freeze_kwargs):
             sys.stdout.write(line + '\n')
diff --git a/src/pip/_internal/compat.py b/src/pip/_internal/compat.py
index fdbfb7dd8d1..70d7730f666 100644
--- a/src/pip/_internal/compat.py
+++ b/src/pip/_internal/compat.py
@@ -60,7 +60,8 @@ def backslashreplace_decode_fn(err):
         return u"".join(u"\\x%x" % c for c in raw_bytes), err.end
     codecs.register_error(
         "backslashreplace_decode",
-        backslashreplace_decode_fn)
+        backslashreplace_decode_fn,
+    )
     backslashreplace_decode = "backslashreplace_decode"
 
 
@@ -88,8 +89,9 @@ def console_to_str(data):
         s = data.decode(encoding)
     except UnicodeDecodeError:
         logger.warning(
-            "Subprocess output does not appear to be encoded as %s" %
-            encoding)
+            "Subprocess output does not appear to be encoded as %s",
+            encoding,
+        )
         s = data.decode(encoding, errors=backslashreplace_decode)
 
     # Make sure we can print the output, by encoding it to the output
diff --git a/src/pip/_internal/download.py b/src/pip/_internal/download.py
index 9da45eac3d8..d6a4358798d 100644
--- a/src/pip/_internal/download.py
+++ b/src/pip/_internal/download.py
@@ -348,8 +348,8 @@ def __init__(self, *args, **kwargs):
             # connection got interrupted in some way. A 503 error in general
             # is typically considered a transient error so we'll go ahead and
             # retry it.
-            # A 500 may indicate transient errror in Amazon S3
-            # A 520 or 527 - may indicate transient errror in CloudFlare
+            # A 500 may indicate transient error in Amazon S3
+            # A 520 or 527 - may indicate transient error in CloudFlare
             status_forcelist=[500, 503, 520, 527],
 
             # Add a small amount of back off between failed requests in
diff --git a/src/pip/_internal/index.py b/src/pip/_internal/index.py
index 7c2d5cf0c2f..ab3a967b13c 100644
--- a/src/pip/_internal/index.py
+++ b/src/pip/_internal/index.py
@@ -253,14 +253,16 @@ def sort_path(path):
                 else:
                     logger.warning(
                         "Url '%s' is ignored: it is neither a file "
-                        "nor a directory.", url)
+                        "nor a directory.", url,
+                    )
             elif is_url(url):
                 # Only add url with clear scheme
                 urls.append(url)
             else:
                 logger.warning(
                     "Url '%s' is ignored. It is either a non-existing "
-                    "path or lacks a specific scheme.", url)
+                    "path or lacks a specific scheme.", url,
+                )
 
         return files, urls
 
@@ -400,13 +402,13 @@ def find_all_candidates(self, project_name):
         index_locations = self._get_index_urls_locations(project_name)
         index_file_loc, index_url_loc = self._sort_locations(index_locations)
         fl_file_loc, fl_url_loc = self._sort_locations(
-            self.find_links, expand_dir=True)
+            self.find_links, expand_dir=True,
+        )
         dep_file_loc, dep_url_loc = self._sort_locations(self.dependency_links)
 
-        file_locations = (
-            Link(url) for url in itertools.chain(
-                index_file_loc, fl_file_loc, dep_file_loc)
-        )
+        file_locations = (Link(url) for url in itertools.chain(
+            index_file_loc, fl_file_loc, dep_file_loc,
+        ))
 
         # We trust every url that the user has given us whether it was given
         #   via --index-url or --find-links
@@ -632,11 +634,13 @@ def _link_package_versions(self, link, search):
                 return
             if ext not in SUPPORTED_EXTENSIONS:
                 self._log_skipped_link(
-                    link, 'unsupported archive format: %s' % ext)
+                    link, 'unsupported archive format: %s' % ext,
+                )
                 return
             if "binary" not in search.formats and ext == wheel_ext:
                 self._log_skipped_link(
-                    link, 'No binaries permitted for %s' % search.supplied)
+                    link, 'No binaries permitted for %s' % search.supplied,
+                )
                 return
             if "macosx10" in link.path and ext == '.zip':
                 self._log_skipped_link(link, 'macosx10 one')
@@ -662,7 +666,8 @@ def _link_package_versions(self, link, search):
         # This should be up by the search.ok_binary check, but see issue 2700.
         if "source" not in search.formats and ext != wheel_ext:
             self._log_skipped_link(
-                link, 'No sources permitted for %s' % search.supplied)
+                link, 'No sources permitted for %s' % search.supplied,
+            )
             return
 
         if not version:
@@ -829,8 +834,8 @@ def get_page(cls, link, skip_archives=True, session=None):
         except requests.HTTPError as exc:
             cls._handle_fail(link, exc, url)
         except SSLError as exc:
-            reason = ("There was a problem confirming the ssl certificate: "
-                      "%s" % exc)
+            reason = "There was a problem confirming the ssl certificate: "
+            reason += str(exc)
             cls._handle_fail(link, reason, url, meth=logger.info)
         except requests.ConnectionError as exc:
             cls._handle_fail(link, "connection error: %s" % exc, url)
@@ -1098,7 +1103,8 @@ def fmt_ctl_formats(fmt_ctl, canonical_name):
 
 def fmt_ctl_no_binary(fmt_ctl):
     fmt_ctl_handle_mutual_exclude(
-        ':all:', fmt_ctl.no_binary, fmt_ctl.only_binary)
+        ':all:', fmt_ctl.no_binary, fmt_ctl.only_binary,
+    )
 
 
 Search = namedtuple('Search', 'supplied canonical formats')
diff --git a/src/pip/_internal/operations/check.py b/src/pip/_internal/operations/check.py
index eef0630fc0a..3855f34edbf 100644
--- a/src/pip/_internal/operations/check.py
+++ b/src/pip/_internal/operations/check.py
@@ -9,8 +9,7 @@ def check_requirements(installed_dists):
         if missing_reqs:
             missing_reqs_dict[dist.key] = missing_reqs
 
-        incompatible_reqs = list(get_incompatible_reqs(
-            dist, installed_dists))
+        incompatible_reqs = list(get_incompatible_reqs(dist, installed_dists))
         if incompatible_reqs:
             incompatible_reqs_dict[dist.key] = incompatible_reqs
 
diff --git a/src/pip/_internal/operations/freeze.py b/src/pip/_internal/operations/freeze.py
index 4455f0c910c..b6821c0e7ef 100644
--- a/src/pip/_internal/operations/freeze.py
+++ b/src/pip/_internal/operations/freeze.py
@@ -209,7 +209,8 @@ def from_dist(cls, dist, dependency_links):
                     )
                 if not svn_location:
                     logger.warning(
-                        'Warning: cannot find svn location for %s', req)
+                        'Warning: cannot find svn location for %s', req,
+                    )
                     comments.append(
                         '## FIXME: could not find svn URL in dependency_links '
                         'for this package:'
diff --git a/src/pip/_internal/req/req_file.py b/src/pip/_internal/req/req_file.py
index 44cccf0cc36..08e1b119f0a 100644
--- a/src/pip/_internal/req/req_file.py
+++ b/src/pip/_internal/req/req_file.py
@@ -131,7 +131,8 @@ def process_line(line, filename, line_number, finder=None, comes_from=None,
 
     # preserve for the nested code path
     line_comes_from = '%s %s (line %s)' % (
-        '-c' if constraint else '-r', filename, line_number)
+        '-c' if constraint else '-r', filename, line_number,
+    )
 
     # yield a line requirement
     if args_str:
@@ -299,7 +300,5 @@ def skip_regex(lines_enum, options):
     skip_regex = options.skip_requirements_regex if options else None
     if skip_regex:
         pattern = re.compile(skip_regex)
-        lines_enum = filterfalse(
-            lambda e: pattern.search(e[1]),
-            lines_enum)
+        lines_enum = filterfalse(lambda e: pattern.search(e[1]), lines_enum)
     return lines_enum
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index 27978d8cbf8..4f6ce4f3e58 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -729,7 +729,8 @@ def install(self, install_options, global_options=None, root=None,
         global_options = global_options if global_options is not None else []
         if self.editable:
             self.install_editable(
-                install_options, global_options, prefix=prefix)
+                install_options, global_options, prefix=prefix,
+            )
             return
         if self.is_wheel:
             version = wheel.wheel_version(self.source_dir)
@@ -756,7 +757,8 @@ def install(self, install_options, global_options=None, root=None,
         with TempDirectory(kind="record") as temp_dir:
             record_filename = os.path.join(temp_dir.path, 'install-record.txt')
             install_args = self.get_install_args(
-                global_options, record_filename, root, prefix)
+                global_options, record_filename, root, prefix,
+            )
             msg = 'Running setup.py install for %s' % (self.name,)
             with open_spinner(msg) as spinner:
                 with indent_log():
@@ -882,7 +884,8 @@ def install_editable(self, install_options,
                 list(install_options),
 
                 cwd=self.setup_py_dir,
-                show_stdout=False)
+                show_stdout=False,
+            )
 
         self.install_succeeded = True
 
@@ -953,7 +956,8 @@ def get_dist(self):
         return pkg_resources.Distribution(
             os.path.dirname(egg_info),
             project_name=dist_name,
-            metadata=metadata)
+            metadata=metadata,
+        )
 
     @property
     def has_hash_options(self):
diff --git a/src/pip/_internal/req/req_set.py b/src/pip/_internal/req/req_set.py
index fb07120e880..fdc293e002e 100644
--- a/src/pip/_internal/req/req_set.py
+++ b/src/pip/_internal/req/req_set.py
@@ -120,7 +120,8 @@ def add_requirement(self, install_req, parent_req_name=None,
                         raise InstallationError(
                             "Could not satisfy constraints for '%s': "
                             "installation from path or url cannot be "
-                            "constrained to a version" % name)
+                            "constrained to a version" % name,
+                        )
                     # If we're now installing a constraint, mark the existing
                     # object for real installation.
                     existing_req.constraint = False
diff --git a/src/pip/_internal/req/req_uninstall.py b/src/pip/_internal/req/req_uninstall.py
index 745d4084454..a3cc7bf66b5 100644
--- a/src/pip/_internal/req/req_uninstall.py
+++ b/src/pip/_internal/req/req_uninstall.py
@@ -371,7 +371,8 @@ def from_dist(cls, dist):
         else:
             logger.debug(
                 'Not sure how to uninstall: %s - Check: %s',
-                dist, dist.location)
+                dist, dist.location,
+            )
 
         # find distutils scripts= scripts
         if dist.has_metadata('scripts') and dist.metadata_isdir('scripts'):
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index 6f7aa73e63d..6b711696520 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -679,7 +679,8 @@ def call_subprocess(cmd, show_stdout=True, cwd=None,
     try:
         proc = subprocess.Popen(
             cmd, stderr=subprocess.STDOUT, stdin=None, stdout=stdout,
-            cwd=cwd, env=env)
+            cwd=cwd, env=env,
+        )
     except Exception as exc:
         logger.critical(
             "Error %s while executing command %s", exc, command_desc,
diff --git a/src/pip/_internal/utils/packaging.py b/src/pip/_internal/utils/packaging.py
index 1df474a8006..98cdb682001 100644
--- a/src/pip/_internal/utils/packaging.py
+++ b/src/pip/_internal/utils/packaging.py
@@ -56,8 +56,9 @@ def check_dist_requires_python(dist):
             )
     except specifiers.InvalidSpecifier as e:
         logger.warning(
-            "Package %s has an invalid Requires-Python entry %s - %s" % (
-                dist.project_name, requires_python, e))
+            "Package %s has an invalid Requires-Python entry %s - %s",
+            dist.project_name, requires_python, e,
+        )
         return
 
 
diff --git a/src/pip/_internal/vcs/bazaar.py b/src/pip/_internal/vcs/bazaar.py
index 7acaf167f85..b4e46e0e1cd 100644
--- a/src/pip/_internal/vcs/bazaar.py
+++ b/src/pip/_internal/vcs/bazaar.py
@@ -91,7 +91,8 @@ def get_url(self, location):
 
     def get_revision(self, location):
         revision = self.run_command(
-            ['revno'], show_stdout=False, cwd=location)
+            ['revno'], show_stdout=False, cwd=location,
+        )
         return revision.splitlines()[-1]
 
     def get_src_requirement(self, dist, location):
diff --git a/src/pip/_internal/vcs/git.py b/src/pip/_internal/vcs/git.py
index d7bc30603cd..3528d8fd9b3 100644
--- a/src/pip/_internal/vcs/git.py
+++ b/src/pip/_internal/vcs/git.py
@@ -205,7 +205,8 @@ def get_url(self, location):
         """Return URL of the first remote encountered."""
         remotes = self.run_command(
             ['config', '--get-regexp', r'remote\..*\.url'],
-            show_stdout=False, cwd=location)
+            show_stdout=False, cwd=location,
+        )
         remotes = remotes.splitlines()
         found_remote = remotes[0]
         for remote in remotes:
@@ -217,7 +218,8 @@ def get_url(self, location):
 
     def get_revision(self, location):
         current_rev = self.run_command(
-            ['rev-parse', 'HEAD'], show_stdout=False, cwd=location)
+            ['rev-parse', 'HEAD'], show_stdout=False, cwd=location,
+        )
         return current_rev.strip()
 
     def _get_subdirectory(self, location):
diff --git a/src/pip/_internal/wheel.py b/src/pip/_internal/wheel.py
index c8887ff10a1..c8fc21518fd 100644
--- a/src/pip/_internal/wheel.py
+++ b/src/pip/_internal/wheel.py
@@ -811,7 +811,8 @@ def build(self, requirements, session, autobuilding=False):
             if req.is_wheel:
                 if not autobuilding:
                     logger.info(
-                        'Skipping %s, due to already being wheel.', req.name)
+                        'Skipping %s, due to already being wheel.', req.name,
+                    )
             elif autobuilding and req.editable:
                 pass
             elif autobuilding and req.link and not req.link.is_artifact:
@@ -831,7 +832,8 @@ def build(self, requirements, session, autobuilding=False):
                             canonicalize_name(req.name)):
                         logger.info(
                             "Skipping bdist_wheel for %s, due to binaries "
-                            "being disabled for it.", req.name)
+                            "being disabled for it.", req.name,
+                        )
                         continue
                 buildset.append(req)
 
@@ -888,7 +890,8 @@ def build(self, requirements, session, autobuilding=False):
                         # extract the wheel into the dir
                         unpack_url(
                             req.link, req.source_dir, None, False,
-                            session=session)
+                            session=session,
+                        )
                 else:
                     build_failure.append(req)
 
diff --git a/tests/unit/test_compat.py b/tests/unit/test_compat.py
index 71d3d576267..37af0f95092 100644
--- a/tests/unit/test_compat.py
+++ b/tests/unit/test_compat.py
@@ -59,7 +59,7 @@ def test_console_to_str(monkeypatch):
 def test_console_to_str_warning(monkeypatch):
     some_bytes = b"a\xE9b"
 
-    def check_warning(msg):
+    def check_warning(msg, *args, **kwargs):
         assert msg.startswith(
             "Subprocess output does not appear to be encoded as")