code: def _accept_header(self):
          
          if not self.VERSION_TO_ACCEPT_HEADER:
              return self.ACCEPT_HEADER
  
          return YagocdUtil.choose_option(
              version_to_options=self.VERSION_TO_ACCEPT_HEADER,
              default=self.ACCEPT_HEADER,
              server_version=self._session.server_version
          )
docs: Method for determining correct `Accept` header.
  
          Different resources and different GoCD version servers prefer
          a diverse headers. In order to manage all of them, this method
          tries to help: if `VERSION_TO_ACCEPT_HEADER` is not provided,
          if would simply return default `ACCEPT_HEADER`.
          Though if some manager specifies `VERSION_TO_ACCEPT_HEADER`
          class variable, then it should be a dictionary: keys should be
          a versions and values should be desired accept headers.
          Choosing is pessimistic: if version of a server is less or
          equal to one of the dictionary, the value of that key would be
          used.
  
          :return: accept header to use in request.