code: def with_claims(self, additional_claims):
          
          new_additional_claims = copy.deepcopy(self._additional_claims)
          new_additional_claims.update(additional_claims or {})
  
          return self.__class__(
              self._signer,
              service_account_email=self._service_account_email,
              scopes=self._scopes,
              token_uri=self._token_uri,
              subject=self._subject,
              project_id=self._project_id,
              additional_claims=new_additional_claims)
docs: Returns a copy of these credentials with modified claims.
  
          Args:
              additional_claims (Mapping[str, str]): Any additional claims for
                  the JWT payload. This will be merged with the current
                  additional claims.
  
          Returns:
              google.auth.service_account.Credentials: A new credentials
                  instance.