code: def get_mail_keys(message, complete=True):
      
  
      if complete:
          log.debug("Get all headers")
          all_headers_keys = {i.lower() for i in message.keys()}
          all_parts = ADDRESSES_HEADERS | OTHERS_PARTS | all_headers_keys
      else:
          log.debug("Get only mains headers")
          all_parts = ADDRESSES_HEADERS | OTHERS_PARTS
  
      log.debug("All parts to get: {}".format(", ".join(all_parts)))
      return all_parts
docs: Given an email.message.Message, return a set with all email parts to get
  
      Args:
          message (email.message.Message): email message object
          complete (bool): if True returns all email headers
  
      Returns:
          set with all email parts