code: def parse_ipv6_literal_host(entity, default_port):
      
      if entity.find(']') == -1:
          raise ValueError("an IPv6 address literal must be "
                           "enclosed in '[' and ']' according "
                           "to RFC 2732.")
      i = entity.find(']:')
      if i == -1:
          return entity[1:-1], default_port
      return entity[1: i], entity[i + 2:]
docs: Validates an IPv6 literal host:port string.
  
      Returns a 2-tuple of IPv6 literal followed by port where
      port is default_port if it wasn't specified in entity.
  
      :Parameters:
          - `entity`: A string that represents an IPv6 literal enclosed
                      in braces (e.g. '[::1]' or '[::1]:27017').
          - `default_port`: The port number to use when one wasn't
                            specified in entity.