freebsd postfix python policyd-spf ip addres validation error

The solution to my Problem was (for now) to add the following lines to the function _cidrmatch in /usr/local/bin/policyd-spf

def _cidrmatch(ip, netwrk)
  netwrk = unicode(netwrk)
  ip = unicode(ip)
  try:
    address = ipaddress.ip_address(ip)

This is done so that the python module ipaddr only has to deal with unicode string (as requested by the error message)
switching to python3 as suggested by other posts on the web did not work for me (maybe some missing dependencies?)

 Stolen from here, but it worked:
https://superuser.com/questions/1253657/freebsd-postfix-python-policyd-spf-ip-addres-validation-error/1253658