Steps to merge two ONNX files into one

1. Introduction This section describes a simple procedure for combining two ONNX into one ONNX. Because it's a pain to modify the original PyTorch program when exporting ONNX from PyTorch. In order to combine two ONNX with this simple procedure, the prerequisites are The number of outputs of the first ONNX must match the number of inputs of the second ONNX. The shape of the output of the first ONN