code: def splitport(host):
      
      global _portprog
      if _portprog is None:
          import re
          _portprog = re.compile('^(.*):([0-9]+)$')
  
      match = _portprog.match(host)
      if match: return match.group(1, 2)
      return host, None
docs: splitport('host:port') --> 'host', 'port'.