Distinguish weight(kernel) in the created graph and params

Questions
1

You know, the following created graph inlcudes input and output nodes, which have shape about weight(kernel), bias and others. And the created params have weight param and bias.
Now I would like to do custom processing for weight(kernel). How to distinguish which weight(kernel) in the following created graph and params?

with relay.build_config(opt_level=3):
graph, lib, params = relay.build(mod,
target=target,
target_host=target_host,
params=params)

Thanks!