def METHOD_NAME(self, backend=None):
    """Returns matrix representation of special gate.
    Args:
        backend (:class:`qibo.backends.abstract.Backend`, optional): backend
        to be used in the execution. If ``None``, it uses
        :class:`qibo.backends.GlobalBackend`. Defaults to ``None``.
    Returns:
        ndarray: Matrix representation of special gate.
    """
    if backend is None:  # pragma: no cover
        backend = GlobalBackend()
    return backend.matrix_fused(self)