Factory: construct an access entry given its API representation

        Args:
            resource (Dict[str, object]):
                Access entry resource representation returned from the API

        Returns:
            google.cloud.bigquery.dataset.AccessEntry:
                Access entry parsed from ``resource``.

        Raises:
            ValueError:
                If the resource has more keys than ``role`` and one additional
                key.

def from_api_repr(cls, resource):
        """Factory: construct an access entry given its API representation

        Args:
            resource (Dict[str, object]):
                Access entry resource representation returned from the API

        Returns:
            google.cloud.bigquery.dataset.AccessEntry:
                Access entry parsed from ``resource``.

        Raises:
            ValueError:
                If the resource has more keys than ``role`` and one additional
                key.
        """
        entry = resource.copy()
        role = entry.pop("role", None)
        entity_type, entity_id = entry.popitem()
        if len(entry) != 0:
            raise ValueError("Entry has unexpected keys remaining.", entry)
        return cls(role, entity_type, entity_id)