How to convert the model input to a .pb file?

[AnatoliyZabrovskiy]

I have a reinforcement learning model in ONNX format. The input to the model in Python code is a NumPy array. For example, it could be np.zeros((1, observation_size)).astype(np.float32) where observation_size = 4. How can I convert this input to a .pb file?
Next, I want to run: 'build/connxr my_model.onnx my_input_0.pb'
Thank you.