docs: def children(self, value):
          """
          Setter for **self.__children** attribute.
  
          :param value: Attribute value.
          :type value: list
          """
  
          if value is not None:
              assert type(value) is list, "'{0}' attribute: '{1}' type is not 'list'!".format("children", value)
              for element in value:
                  assert issubclass(element.__class__,
                                    AbstractNode), "'{0}' attribute: '{1}' is not a '{2}' subclass!".format(
                      "children", element, AbstractNode.__class__.__name__)
          self.__children = value