def feature_lyr_osr(feature_lyr):
    """Return the spatial reference of a feature layer

    Args:
        feature_lyr (:class:`ogr.Layer`): OGR feature layer from
            which you desire the :class:`osr.SpatialReference`

    Returns:
        osr.SpatialReference: the :class:`osr.SpatialReference` object
            of the input feature layer

    """
    return feature_lyr.GetSpatialRef()