QueryContainers from either SMARTS or SMILES give errors even with the simplest requests (see example). Substructure search works with just MoleculeContainers.

from chython import QueryContainer, smiles
tmp = QueryContainer('O=C')
diketone = smiles("C1C(=O)C(C(CC1)(=O))C")
tmp2 = smiles('O=CC(C)C=O')

tmp < diketone

gives an error (IndexError: tuple index out of range).

tmp2 < diketone

works as normal.