prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  No module named 'six'
  Flask's Tox/Travis builds all started failing. Looks like a new version of setuptools was just released that has a problem with six.
  
  ~~~pytb
  Obtaining file:///home/david/Projects/flask
  Installing collected packages: Flask
    Running setup.py develop for Flask
      Complete output from command /home/david/Projects/flask/.tox/py/bin/python3 -c "import setuptools, tokenize;__file__='/home/david/Projects/flask/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" develop --no-deps:
      /home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py:336: UserWarning: Normalizing '0.13-dev' to '0.13.dev0'
        normalized_version,
      Traceback (most recent call last):
        File "<string>", line 1, in <module>
        File "/home/david/Projects/flask/setup.py", line 109, in <module>
          '''
        File "/usr/lib64/python3.6/distutils/core.py", line 134, in setup
          ok = dist.parse_command_line()
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py", line 363, in parse_command_line
          result = _Distribution.parse_command_line(self)
        File "/usr/lib64/python3.6/distutils/dist.py", line 472, in parse_command_line
          args = self._parse_command_opts(parser, args)
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py", line 674, in _parse_command_opts
          nargs = _Distribution._parse_command_opts(self, parser, args)
        File "/usr/lib64/python3.6/distutils/dist.py", line 528, in _parse_command_opts
          cmd_class = self.get_command_class(command)
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py", line 495, in get_command_class
          self.cmdclass[command] = cmdclass = ep.load()
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2303, in load
          return self.resolve()
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2309, in resolve
          module = __import__(self.module_name, fromlist=['__name__'], level=0)
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/command/develop.py", line 11, in <module>
          from setuptools.command.easy_install import easy_install
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/command/easy_install.py", line 49, in <module>
          from setuptools.py27compat import rmtree_safe
        File "/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/py27compat.py", line 7, in <module>
          import six
      ModuleNotFoundError: No module named 'six'
  ~~~
  
  Example failed build log: https://travis-ci.org/pallets/flask/jobs/238166427#L242
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `setuptools/py27compat.py`
  Content:
  ```
  1 """
  2 Compatibility Support for Python 2.7 and earlier
  3 """
  4 
  5 import platform
  6 
  7 import six
  8 
  9 
  10 def get_all_headers(message, key):
  11     """
  12     Given an HTTPMessage, return all headers matching a given key.
  13     """
  14     return message.get_all(key)
  15 
  16 
  17 if six.PY2:
  18     def get_all_headers(message, key):
  19         return message.getheaders(key)
  20 
  21 
  22 linux_py2_ascii = (
  23     platform.system() == 'Linux' and
  24     six.PY2
  25 )
  26 
  27 rmtree_safe = str if linux_py2_ascii else lambda x: x
  28 """Workaround for http://bugs.python.org/issue24672"""
  29
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/setuptools/py27compat.py b/setuptools/py27compat.py
  --- a/setuptools/py27compat.py
  +++ b/setuptools/py27compat.py
  @@ -4,7 +4,7 @@
   
   import platform
   
  -import six
  +from setuptools.extern import six
   
   
   def get_all_headers(message, key):
  
verification_info: {"golden_diff": "diff --git a/setuptools/py27compat.py b/setuptools/py27compat.py\n--- a/setuptools/py27compat.py\n+++ b/setuptools/py27compat.py\n@@ -4,7 +4,7 @@\n \n import platform\n \n-import six\n+from setuptools.extern import six\n \n \n def get_all_headers(message, key):\n", "issue": "No module named 'six'\nFlask's Tox/Travis builds all started failing. Looks like a new version of setuptools was just released that has a problem with six.\r\n\r\n~~~pytb\r\nObtaining file:///home/david/Projects/flask\r\nInstalling collected packages: Flask\r\n  Running setup.py develop for Flask\r\n    Complete output from command /home/david/Projects/flask/.tox/py/bin/python3 -c \"import setuptools, tokenize;__file__='/home/david/Projects/flask/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\\r\\n', '\\n');f.close();exec(compile(code, __file__, 'exec'))\" develop --no-deps:\r\n    /home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py:336: UserWarning: Normalizing '0.13-dev' to '0.13.dev0'\r\n      normalized_version,\r\n    Traceback (most recent call last):\r\n      File \"<string>\", line 1, in <module>\r\n      File \"/home/david/Projects/flask/setup.py\", line 109, in <module>\r\n        '''\r\n      File \"/usr/lib64/python3.6/distutils/core.py\", line 134, in setup\r\n        ok = dist.parse_command_line()\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py\", line 363, in parse_command_line\r\n        result = _Distribution.parse_command_line(self)\r\n      File \"/usr/lib64/python3.6/distutils/dist.py\", line 472, in parse_command_line\r\n        args = self._parse_command_opts(parser, args)\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py\", line 674, in _parse_command_opts\r\n        nargs = _Distribution._parse_command_opts(self, parser, args)\r\n      File \"/usr/lib64/python3.6/distutils/dist.py\", line 528, in _parse_command_opts\r\n        cmd_class = self.get_command_class(command)\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/dist.py\", line 495, in get_command_class\r\n        self.cmdclass[command] = cmdclass = ep.load()\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/pkg_resources/__init__.py\", line 2303, in load\r\n        return self.resolve()\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/pkg_resources/__init__.py\", line 2309, in resolve\r\n        module = __import__(self.module_name, fromlist=['__name__'], level=0)\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/command/develop.py\", line 11, in <module>\r\n        from setuptools.command.easy_install import easy_install\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/command/easy_install.py\", line 49, in <module>\r\n        from setuptools.py27compat import rmtree_safe\r\n      File \"/home/david/Projects/flask/.tox/py/lib/python3.6/site-packages/setuptools/py27compat.py\", line 7, in <module>\r\n        import six\r\n    ModuleNotFoundError: No module named 'six'\r\n~~~\r\n\r\nExample failed build log: https://travis-ci.org/pallets/flask/jobs/238166427#L242\n", "before_files": [{"content": "\"\"\"\nCompatibility Support for Python 2.7 and earlier\n\"\"\"\n\nimport platform\n\nimport six\n\n\ndef get_all_headers(message, key):\n    \"\"\"\n    Given an HTTPMessage, return all headers matching a given key.\n    \"\"\"\n    return message.get_all(key)\n\n\nif six.PY2:\n    def get_all_headers(message, key):\n        return message.getheaders(key)\n\n\nlinux_py2_ascii = (\n    platform.system() == 'Linux' and\n    six.PY2\n)\n\nrmtree_safe = str if linux_py2_ascii else lambda x: x\n\"\"\"Workaround for http://bugs.python.org/issue24672\"\"\"\n", "path": "setuptools/py27compat.py"}], "after_files": [{"content": "\"\"\"\nCompatibility Support for Python 2.7 and earlier\n\"\"\"\n\nimport platform\n\nfrom setuptools.extern import six\n\n\ndef get_all_headers(message, key):\n    \"\"\"\n    Given an HTTPMessage, return all headers matching a given key.\n    \"\"\"\n    return message.get_all(key)\n\n\nif six.PY2:\n    def get_all_headers(message, key):\n        return message.getheaders(key)\n\n\nlinux_py2_ascii = (\n    platform.system() == 'Linux' and\n    six.PY2\n)\n\nrmtree_safe = str if linux_py2_ascii else lambda x: x\n\"\"\"Workaround for http://bugs.python.org/issue24672\"\"\"\n", "path": "setuptools/py27compat.py"}]}