The way to handle this issue would be add these characters 
'%/:=&?~#+!$,;'@()*[]' to always_safe list.

There has been a similar issue in the past Issue918368, tough in a
different context.

And if you see, urllib.urlopen function always passes these values as 
the safe parameter to the quote function,

fullurl = quote(fullurl, safe="%/:=&?~#+!$,;'@()*[]")

Handling of unicode is a different issue, but for the current report,
this change should suffice.