def METHOD_NAME(con):
    @udf([dt.string], dt.double)
    def my_str_len(s):
        return s.length
    s = ibis.literal("abcd")
    expr = my_str_len(s) + my_str_len(s)
    add = expr.op()
    # generated javascript is identical
    assert add.left.sql == add.right.sql
    assert con.execute(expr) == 8.0