def findNestedUnions(self, lst):
        '''
        Recursive helper function for finding nested unions.  If this node is a class or
        struct it may have had a union added to its child list.  When this occurred, the
        union was removed from ``self.unions`` in the :class:`~exhale.graph.ExhaleRoot`
        class and needs to be rediscovered by calling this method on all of its
        children.  If this node is a union, it is because a parent class or struct
        called this method, in which case it is added to ``lst``.

        **Note**: this is used slightly differently than nested directories, namespaces,
        and classes will be.  Refer to
        :func:`~exhale.graph.ExhaleRoot.generateNodeDocuments`.

        :Parameters:
            ``lst`` (list)
                The list each union is to be appended to.
        '''
        if self.kind == "union":
            lst.append(self)
        for c in self.children:
            c.findNestedUnions(lst)