Packets are not being modified

[Mou299]

Hi, I'm trying to modify some packets but the tool doesn't work.
I have already python 3.8.2 installed and have installed Polymorph as you said to do.
When I'm creating the function in the captured template the added functions don't work at all.
I continue to see the "[*] Waiting for packets..." message but nothing happens, even if ICMP packets are travelling.
I've followed what you said in the guide:

The strange thing is that it captures the packets as normal, but if I want to do another thing it doesn't work..

I tried to send ICMP packets from the local machine where polymorph is running and from another one in the same network and it doesn't work with both