docs: def select_header_content_type(self, content_types):
          """
          Returns `Content-Type` based on an array of content_types provided.
  
          :param content_types: List of content-types.
          :return: Content-Type (e.g. application/json).
          """
          if not content_types:
              return 'application/json'
  
          content_types = list(map(lambda x: x.lower(), content_types))
  
          if 'application/json' in content_types or '*/*' in content_types:
              return 'application/json'
          else:
              return content_types[0]