fix: add getter and setter methods for struct_refs

modules/io/pymod/export_mmcif_io.cc

@@ -525,6 +525,8 @@ void export_mmcif_io()
                                    return_value_policy<copy_const_reference>()))
     .def("SetStructDetails", &MMCifInfo::SetStructDetails)
     .def("GetStructDetails", &MMCifInfo::GetStructDetails)
+    .def("SetStructRefs", &MMCifInfo::SetStructRefs)
+    .def("GetStructRefs", &MMCifInfo::GetStructRefs)
     .def("SetObsoleteInfo", &MMCifInfo::SetObsoleteInfo)
     .def("GetObsoleteInfo", &MMCifInfo::GetObsoleteInfo)
     .def("AddMMCifPDBChainTr", &MMCifInfo::AddMMCifPDBChainTr)