def local_constraints(self):
        """
        Return the constraints defined in the local AVM.
        """
        cs = []
        for feat, val in self._avm.items():
            try:
                if val.supertypes and not val._avm:
                    cs.append((feat, val))
                else:
                    for subfeat, subval in val.features():
                        cs.append(('{}.{}'.format(feat, subfeat), subval))
            except AttributeError:
                cs.append((feat, val))
        return cs
Return the constraints defined in the local AVM.