Fix flake8-return warning

RET503 Missing explicit `return` at the end of function able
       to return non-`None` value

Author: DimitriPapadopoulos

pkg_resources/__init__.py

@@ -1127,8 +1127,7 @@ def obtain(self, requirement, installer=None):
         None is returned instead.  This method is a hook that allows subclasses
         to attempt other ways of obtaining a distribution before falling back
         to the `installer` argument."""
-        if installer is not None:
-            return installer(requirement)
+        return installer(requirement) if installer else None
 
     def __iter__(self):
         """Yield the unique project names of the available distributions"""
@@ -3210,6 +3209,7 @@ def _find_adapter(registry, ob):
     for t in types:
         if t in registry:
             return registry[t]
+    return None
 
 
 def ensure_directory(path):

setuptools/command/bdist_egg.py

@@ -419,6 +419,7 @@ def can_scan():
         "Please ask the author to include a 'zip_safe'"
         " setting (either True or False) in the package's setup.py"
     )
+    return False
 
 
 # Attribute names of options for commands that might need to be convinced to

setuptools/command/build_ext.py

@@ -76,6 +76,7 @@ def get_abi3_suffix():
             return suffix
         elif suffix == '.pyd':  # Windows
             return suffix
+    return None
 
 
 class build_ext(_build_ext):

setuptools/command/develop.py

@@ -157,6 +157,8 @@ def install_egg_scripts(self, dist):
                 script_text = strm.read()
             self.install_script(dist, script_name, script_text, script_path)
 
+        return None
+
     def install_wrapper_scripts(self, dist):
         dist = VersionlessRequirement(dist)
         return easy_install.install_wrapper_scripts(self, dist)

setuptools/command/easy_install.py

@@ -741,6 +741,7 @@ def install_item(self, spec, download, tmpdir, deps, install_needed=False):
             for dist in dists:
                 if dist in spec:
                     return dist
+        return None
 
     def select_scheme(self, name):
         try:

setuptools/command/install.py

@@ -71,6 +71,7 @@ def handle_extra_path(self):
         # command without --root or --single-version-externally-managed
         self.path_file = None
         self.extra_dirs = ''
+        return None
 
     def run(self):
         # Explicit request for old-style install?  Just do it
@@ -83,6 +84,8 @@ def run(self):
         else:
             self.do_egg_install()
 
+        return None
+
     @staticmethod
     def _called_from_setup(run_frame):
         """
@@ -114,6 +117,8 @@ def _called_from_setup(run_frame):
 
             return caller_module == 'distutils.dist' and info.function == 'run_commands'
 
+        return False
+
     def do_egg_install(self):
         easy_install = self.distribution.get_command_class('easy_install')
 

setuptools/depends.py

@@ -159,6 +159,7 @@ def extract_constant(code, symbol, default=-1):
         else:
             const = default
 
+    return None
 
 def _update_globals():
     """

setuptools/dist.py

@@ -778,6 +778,8 @@ def has_contents_for(self, package):
             if p == package or p.startswith(pfx):
                 return True
 
+        return False
+
     def _exclude_misc(self, name, value):
         """Handle 'exclude()' for list/tuple attrs without a special handler"""
         if not isinstance(value, sequence):

setuptools/msvc.py

@@ -577,6 +577,7 @@ def lookup(self, key, name):
             finally:
                 if bkey:
                     closekey(bkey)
+        return None
 
 
 class SystemInfo:
@@ -823,6 +824,7 @@ def WindowsSdkVersion(self):
             return '8.1', '8.1a'
         elif self.vs_ver >= 14.0:
             return '10.0', '8.1'
+        return None
 
     @property
     def WindowsSdkLastVersion(self):
@@ -914,6 +916,8 @@ def WindowsSDKExecutablePath(self):
             if execpath:
                 return execpath
 
+        return None
+
     @property
     def FSharpInstallDir(self):
         """
@@ -946,6 +950,8 @@ def UniversalCRTSdkDir(self):
             if sdkdir:
                 return sdkdir or ''
 
+        return None
+
     @property
     def UniversalCRTSdkLastVersion(self):
         """

setuptools/package_index.py

@@ -406,6 +406,7 @@ def url_ok(self, url, fatal=False):
             raise DistutilsError(msg % url)
         else:
             self.warn(msg, url)
+            return False
 
     def scan_egg_links(self, search_path):
         dirs = filter(os.path.isdir, search_path)
@@ -648,6 +649,8 @@ def find(req, env=None):
                     if os.path.exists(dist.download_location):
                         return dist
 
+            return None
+
         if force_scan:
             self.prescan()
             self.find_packages(requirement)
@@ -671,6 +674,7 @@ def find(req, env=None):
                 (source and "a source distribution of " or ""),
                 requirement,
             )
+            return None
         else:
             self.info("Best match: %s", dist)
             return dist.clone(location=dist.download_location)
@@ -1034,6 +1038,7 @@ def find_credential(self, url):
         for repository, cred in self.creds_by_repository.items():
             if url.startswith(repository):
                 return cred
+        return None
 
 
 def open_with_auth(url, opener=urllib.request.urlopen):