Lua/Wireshark: No module named 'pymavlink.tools'

[guglie]

I'm trying to generate a Lua dissector for Wireshark.

Following the instructions on https://github.com/ArduPilot/pymavlink/blob/c18db673f0214b683bc330587bc11ce2818a8e8d/generator/mavgen_wlua.py#L9

I get this error ModuleNotFoundError: No module named 'pymavlink.tools'

I know that a partial solution could be the one proposed at https://github.com/ArduPilot/pymavlink/issues/133 but how can I solve this issue?