code: def python_file_with_version(self):
          
          default = None
          if self.config is None:
              return default
          try:
              result = self.config.get('zest.releaser',
                                       'python-file-with-version')
          except (NoSectionError, NoOptionError, ValueError):
              return default
          return result
docs: Return Python filename with ``__version__`` marker, if configured.
  
          Enable this by adding a ``python-file-with-version`` option::
  
              [zest.releaser]
              python-file-with-version = reinout/maurits.py
  
          Return None when nothing has been configured.