docs: def __copy(self, other):
          """Copy constructor."""
          self.__data = copy.deepcopy(other.data)
          self.__classes = copy.deepcopy(other.classes)
          self.__labels = copy.deepcopy(other.labels)
          self.__dtype = copy.deepcopy(other.dtype)
          self.__description = copy.deepcopy(other.description)
          self.__feature_names = copy.deepcopy(other.feature_names)
          self.__num_features = copy.deepcopy(other.num_features)
  
          return self