def parse_atom_site(self, name, attributes):
        '''Parse the atom tag attributes. Most atom tags do not have attributes.'''
        if name == "PDBx:pdbx_PDB_ins_code":
            assert(not(self.current_atom_site.ATOMResidueiCodeIsNull))
            if attributes.get('xsi:nil') == 'true':
                self.current_atom_site.ATOMResidueiCodeIsNull = True
        if name == "PDBx:auth_asym_id":
            assert(not(self.current_atom_site.PDBChainIDIsNull))
            if attributes.get('xsi:nil') == 'true':
                self.current_atom_site.PDBChainIDIsNull = True
Parse the atom tag attributes. Most atom tags do not have attributes.