def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def test_can_encode_relationship_with_properties(self):
        a = Node("Person", name="Alice")
        b = Node("Person", name="Bob")
        ab = KNOWS(a, b, since=1999)
        encoded = cypher_repr(ab, related_node_template="{property.name}")
        self.assertEqual("(Alice)-[:KNOWS {since: 1999}]->(Bob)", encoded)