def METHOD_NAME(z_slice):
    """
    Fill holes in the segmentation.
    :param z_slice: int 2d-array: Input 2D segmentation.
    :return: int 2d-array: Output segmentation with holes filled
    """
    assert z_slice.dtype == np.dtype('int')
    return binary_fill_holes(z_slice, structure=np.ones((3, 3))).astype(int)