Check that the wildtype of the Mutation object matches the PDB sequence.

def assert_wildtype_matches(self, mutation):
        '''Check that the wildtype of the Mutation object matches the PDB sequence.'''
        readwt = self.getAminoAcid(self.getAtomLine(mutation.Chain, mutation.ResidueID))
        assert(mutation.WildTypeAA == residue_type_3to1_map[readwt])