code: def _convert_dict_to_list_tuples(self, headers_dict):
          # type: (Dict[str, str]) -> List[Tuple[str, str]]
          
          headers_list = []
          if headers_dict is not None:
              for key, values in six.iteritems(headers_dict):
                  for value in values.split(","):
                      value = value.strip()
                      if value is not None and value is not '':
                          headers_list.append((key, value.strip()))
          return headers_list
docs: Convert headers dict to list of string tuples format for
          `ApiClientResponse` headers variable.
  
          :param headers_dict: Dictionary of headers in keys as strings
              and values as comma separated strings
          :type headers_dict: Dict[str, str]
          :return: List of tuples made up of two element strings from
              headers of client response
          :rtype: List[Tuple[str, str]]