def test_iadd(self, evt):
        rval = event.ReturnValue(append_events=[evt])
        rval2 = event.ReturnValue(eat=True, append_events=[evt])
        rset = event.ResultSet()

        rset += rval
        rset += rval2
        rset += None
        assert rset.eat
        assert rset.append_events == [evt, evt]
def split_container(container, iter):
	root = Tree(container)
	if iter != 0:
		sr = random_split(container)
		if sr!=None:
			root.lchild = split_container(sr[0], iter-1)
			root.rchild = split_container(sr[1], iter-1)
	return root