The shape of the provided factors is not verified to be correct. See TODO in [src/scalib_ext/scalib-py/src/factor_graph.rs](https://github.com/simple-crypto/SCALib/pull/129/files/e512ef5ea65082ef87d156ff7c5405b9a8a707f9#diff-614791f11ecb9c7c080caaecfff2752971a991f4f65de22e131871306b689b45) (line 188). Follow-up from #129 cc @rishubn