The current list of sync map fragments
        which are (the values of) the leaves
        of the sync map tree.

        :rtype: list of :class:`~aeneas.syncmap.fragment.SyncMapFragment`

        .. versionadded:: 1.7.0

def leaves(self, fragment_type=None):
        """
        The current list of sync map fragments
        which are (the values of) the leaves
        of the sync map tree.

        :rtype: list of :class:`~aeneas.syncmap.fragment.SyncMapFragment`

        .. versionadded:: 1.7.0
        """
        leaves = self.fragments_tree.vleaves_not_empty
        if fragment_type is None:
            return leaves
        return [l for l in leaves if l.fragment_type == fragment_type]