Function ZL_Compressor_Graph_getBaseGraphID 

pub unsafe extern "C" fn ZL_Compressor_Graph_getBaseGraphID(
    compressor: *const ZL_Compressor,
    graphid: ZL_GraphID,
) -> ZL_GraphID

@returns If the provided @p graphid was created by modifying another existing graph, i.e., its type is ZL_GraphType_parameterized, the ZL_GraphID of that other graph. Otherwise, it returns ZL_GRAPH_ILLEGAL.