xtuml/meta.py
def compute_lookup_key(self, from_instance):
        '''
        Compute the lookup key for an instance, i.e. a foreign key that
        can be used to identify an instance at the end of the link.
        '''
        kwargs = dict()
        for attr, other_attr in self.key_map.items():
            if _is_null(from_instance, attr):
                return None
            
            if attr in from_instance.__dict__:
                kwargs[other_attr] = from_instance.__dict__[attr]
            else:
                kwargs[other_attr] = getattr(from_instance, attr)

        return frozenset(tuple(kwargs.items()))
def compute_lookup_key(self, from_instance):
        '''
        Compute the lookup key for an instance, i.e. a foreign key that
        can be used to identify an instance at the end of the link.
        '''
        kwargs = dict()
        for attr, other_attr in self.key_map.items():
            if _is_null(from_instance, attr):
                return None
            
            if attr in from_instance.__dict__:
                kwargs[other_attr] = from_instance.__dict__[attr]
            else:
                kwargs[other_attr] = getattr(from_instance, attr)

        return frozenset(tuple(kwargs.items()))
Compute the lookup key for an instance, i.e. a foreign key that
        can be used to identify an instance at the end of the link.