def is_leaf(self):
return self._my_map['<STR_LIT>']<EOL>
Tests if this node is a leaf in the hierarchy (has no children).

        A node may have no more children available in this node
        structure but is not a leaf in the hierarchy. If both
        ``is_leaf()`` and ``has_children()`` is false, the children of
        this node may be accessed thorugh another node structure
        retrieval.

        return: (boolean) - ``true`` if this node is a leaf in the
                hierarchy, ``false`` otherwise
        *compliance: mandatory -- This method must be implemented.*