ORT fails on unused input in a function

[justinchuby]

In the example below, self was not used in the function, and ORT complains with failed validating the check: !(it.GetName().empty()) (microsoft/onnxruntime#13278)

@torch_op("aten::copy")
def aten_copy(
    self: TTensor, src: TTensor, non_blocking: bool = False  # pylint: disable=unused-argument
) -> TTensor:
    """copy(Tensor self, Tensor src, bool non_blocking=False) -> Tensor"""

    self = op.Identity(src)
    return self

cc @gramalingam @xiaowuhu @fatcat-z @titaiwangms

[justinchuby]

microsoft/onnxruntime#15046

onnx/onnx#4996