code: def generate_broadcast_to(node_name, x, y, out_name, axis, base_name, func_counter):
      
      bt = nnabla_pb2.Function()
      bt.type = "BroadcastTo"
      set_function_name(bt, node_name, base_name, func_counter)
      bt.input.extend([x, y])
      bt.output.extend([out_name])
      btp = bt.broadcast_to_param
      btp.axis = axis
      return bt
docs: Generate a BroadcastTo operator to brodcast specified buffer