Class A

test/sql/test_external_traversal.py:68–87

        # define deep equality semantics as well as deep
        # identity semantics.
        class A(ClauseElement):
            __visit_name__ = "a"
            _traverse_internals = []

            def __init__(self, expr):
                self.expr = expr

            def is_other(self, other):
                return other is self

            __hash__ = ClauseElement.__hash__

            def __eq__(self, other):
                return other.expr == self.expr

            def __ne__(self, other):
                return other.expr != self.expr

            def __str__(self):
                return "A(%s)" % repr(self.expr)

        class B(ClauseElement):
            __visit_name__ = "b"