def METHOD_NAME():
    class MyExpr(ir.Expr):
        pass
    class MyExprNode(ops.Node):
        foo: ops.Value[dt.String, ds.Any]
        bar: ops.Value[dt.Numeric, ds.Any]
        def to_expr(self):
            return MyExpr(self)
    op = MyExprNode("Hello!", 42.3)
    expr = op.to_expr()
    graph = viz.to_graph(expr)
    assert key(expr.op()) in graph.source