When using npsocket for cross platform transfers (i.e. between macos and windows or linux and windows) it is important to add the Indianess specfifier in teh pack and unpack routine. struct,pack("L"...) or struct.unpack("L",...) should have an indianess specficer infront of the L, for instance "!L" this will prevent the pickle problem of invalid loadkey..
When using npsocket for cross platform transfers (i.e. between macos and windows or linux and windows) it is important to add the Indianess specfifier in teh pack and unpack routine. struct,pack("L"...) or struct.unpack("L",...) should have an indianess specficer infront of the L, for instance "!L" this will prevent the pickle problem of invalid loadkey..