Lookup in web browser, options login, etc all result in picard crashing. I've found the error below each time this happens. Problem appears to be an issue related to the call to the webbrowser.py library. 

Sep 06 15:26:56 artemis python[17021]: Traceback (most recent call last):
File "/usr/lib/python3.7/site-packages/picard/ui/options/general.py", line 107, in login
webbrowser2.open(authorization_url)
File "/usr/lib/python3.7/site-packages/picard/util/webbrowser2.py", line 35, in open
webbrowser.open(string_(url))
File "/usr/lib/python3.7/webbrowser.py", line 75, in open
register_standard_browsers()
File "/usr/lib/python3.7/webbrowser.py", line 567, in register_standard_browsers
cmd = _synthesize(cmdline, -1)
File "/usr/lib/python3.7/webbrowser.py", line 116, in _synthesize
register(browser, None, controller, update_tryorder)
TypeError: register() takes from 2 to 3 positional arguments but 4 were given