Generate a resource for :meth:`_begin`.

def to_api_repr(self):
        """Generate a resource for :meth:`_begin`."""
        configuration = self._configuration.to_api_repr()
        if self.source_uris is not None:
            _helpers._set_sub_prop(
                configuration, ["load", "sourceUris"], self.source_uris
            )
        _helpers._set_sub_prop(
            configuration, ["load", "destinationTable"], self.destination.to_api_repr()
        )

        return {
            "jobReference": self._properties["jobReference"],
            "configuration": configuration,
        }