code: def _parse_config_file_impl(filename):
      
      api_key = None
      email = None
  
      try:
          doc = yaml.load(file(filename).read())
          
          email = doc['credentials']['email']
          api_key = doc['credentials']['api_key']
      except (KeyError, TypeError):
          print(INVALID_FILE)
          return None, None
  
      except yaml.scanner.ScannerError, e:
          print(SYNTAX_ERROR_FILE % (e.problem, e.problem_mark.line))
          return None, None
  
      # Just in case, we don't want the auth to fail because of a space
      email = email.strip()
      api_key = api_key.strip()
  
      if not is_valid_api_key(api_key):
          cli_logger.debug(INVALID_UUID)
          api_key = None
  
      if not is_valid_email(email):
          cli_logger.debug('Invalid email address: %s' % email)
          email = None
  
      return email, api_key
docs: Format for the file is:
      
           credentials:
               email: ...
               api_token: ...
      
      :param filename: The filename to parse
      :return: A tuple with:
                  - email
                  - api_token