Cannot install Electrum in Whonix

[benny81]

Hi,
I cannot install latest version 3.1.3 of Electrum in Whonix (I have no previous version of Electrum). I have Virtualbox version 5212 and Tor 7.5.4. I run Whonix in Windows 7.

Install dependencies works fine to install in the terminal. But the "install Electrum" line won't work. It starts unpacking/downloading but then there comes a long error message (most in red letters) that starts with: "Exception Traceback (most recent call last):" and it ends with "NameError: name 'platform system is not defined' storing debug log for failure"...  Between this there are much more. Does anyone know how to fix this? I would be very greatful.

Best regards
Benny