How to add empty input to a node

hi~Now I am adding a fuse pass

Now I have encountered a problem, how to add an empty input to a node, Node->addInput seems to be unable to add an empty input

Call the following api in python

node_def = helper.make_node(
    'Attention', # node name
    ['p2o.Add.6', 'qkv_weights', 'qkv_bias', '', '', 'extra_add_qk'],
    # ['p2o.Add.6', 'qkv_weights', 'qkv_bias', 'mask_index'],
    ['Y'], # outputs
    name='Attention',
    domain="com.microsoft",
    # attributes
    num_heads=9,
    unidirectional=0,
    )

You can create an Attention node with empty fourth and fifth inputs：

How to create it in C++，thanks a lot~

[HSQ79815]

@wjj19950828

auto* empty_node = g->create(kUndefined, 1);
empty_node->output()->setUniqueName(""); // empty_node->output() is a `Value` that represents a empty tensor 

empty_node->insertBefore(node); // insert empty_node to node lists that should be topo sort

node->addInput(empty_node->output())

Are you able to use the above codes to verifying again ?

[HSQ79815]

@wjj19950828 Great, I will debug it sooner