code: def select_header_accept(self, accepts):
          
          if not accepts:
              return
  
          accepts = [x.lower() for x in accepts]
  
          if 'application/json' in accepts:
              return 'application/json'
          else:
              return ', '.join(accepts)
docs: Returns `Accept` based on an array of accepts provided.
  
          :param accepts: List of headers.
          :return: Accept (e.g. application/json).