Output input = ops::Const(s.WithOpName("const1"), 1, {2});
    NameAttrList true_fn;
    true_fn.set_name("true_fn");
    NameAttrList false_fn;
    false_fn.set_name("false_fn");
    auto if_op = ops::If(s.WithOpName("if"), cond,
                         std::initializer_list<Input>{cond, input}, {DT_INT32},
                         true_fn, false_fn);
    ops::_Retval retval(s.WithOpName("retval"), if_op.output[0], 0);