The normalization pattern for pyridine N-oxide is not specific enough

[ptosco]

Reported by JP Ebejer:

from rdkit import Chem
from rdkit.Chem.MolStandardize import rdMolStandardize

m = Chem.MolFromSmiles('Cn1c(=O)c2nc[nH][n+](=O)c2n(C)c1=O')
m

rdMolStandardize.Cleanup(m)
RDKit ERROR: [19:20:42] Can't kekulize mol.  Unkekulized atoms: 0 3 4 6 7

The molecule is not actually a pyridine N-oxide, rather the oxy tautomer of a N-hydroxypyridinium ion, but it hits the pyridine N-oxide normalization pattern because the latter is not sufficiently specific.