RecursionError: maximum recursion depth exceeded while calling a Python object about arpeggio HOT 4 CLOSED

from __future__ import unicode_literals
from arpeggio import *
from arpeggio import RegExMatch as _
from arpeggio.cleanpeg import ParserPEG


def number_token():                         return _(r'(\d+|\d+\.\d*|\d*\.\d+)')
def identifier_token():                     return _(r'[a-zA-Z_][a-zA-Z0-9_]*')
def unqualified_identifier_expression():    return identifier_token
def qualified_identifier_expression():      return identifier_token, ZeroOrMore(".", identifier_token)
def unary_expression():                     return [number_token, qualified_identifier_expression]

def lvalue_expression():                    return qualified_identifier_expression
def rvalue_expression():                    return expression

def expression():                           return [compound_expression, unary_expression]
def compound_expression():                  return qualified_identifier_expression,\
                                                   ZeroOrMore([method_call_par, index_par])
def method_call_par():                      return  "(", Optional( rvalue_expression, ZeroOrMore( ",", rvalue_expression)), ")"
def index_par():                            return "[", rvalue_expression, ZeroOrMore( ",", rvalue_expression ),    "]"

def belang():                               return ZeroOrMore(expression), EOF

parser = ParserPython(belang, debug=True)
parser.parse('a [0](1)[2]')