code: func (n Network) Contains(nn NetworkNumber) bool {
  	if len(n.Mask) != len(nn) {
  		return false
  	}
  	if nn[0]&n.Mask[0] != n.Number[0] {
  		return false
  	}
  	if len(nn) == IPv6Uint32Count {
  		return nn[1]&n.Mask[1] == n.Number[1] && nn[2]&n.Mask[2] == n.Number[2] && nn[3]&n.Mask[3] == n.Number[3]
  	}
  	return true
  }
docs: // Contains returns true if NetworkNumber is in range of Network, false
  // otherwise.