SMILESParser incorrectly converts c1ccccc1 to an
aromatic. Lower case subset elements actually
represent sp2 hybridization, and not aromaticity,
though these often coincide. Moreover, lower case 'c'
is mostly used (incorrectly) to indicate
aromaticity. See "The full SMILES language allows
sp2-hybridized atoms to be indicated by writing the
atomic symbol in lower case." from