code: def parse_bind_address(address, default=('localhost', 8080)):
      
      if ':' in address:
          host, port = address.split(':', 1)
          port = int(port)
      elif re.match('^\d+$', address):
          host = default[0]
          port = int(address)
      else:
          host = address
          port = default[1]
      return host, port
docs: >>> parse_bind_address('80')
      ('localhost', 80)
      >>> parse_bind_address('0.0.0.0')
      ('0.0.0.0', 8080)
      >>> parse_bind_address('0.0.0.0:8081')
      ('0.0.0.0', 8081)