@abc.abstractmethod<EOL><INDENT>def has_children(self):<DEDENT>
return<EOL>
Tests if any children are available in this node structure.

        There may be no more children available in this node structure
        but this node may have children in the hierarchy.

        :return: ``true`` if this node has children, ``false`` otherwise
        :rtype: ``boolean``


        *compliance: mandatory -- This method must be implemented.*