Pylint 抱怨 NLTK 包的特定文件的循环导入带有 R0401 错误代码，例如
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk -> nltk.internals)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.corpus -> nltk.tokenize -> nltk.tokenize.punkt -> nltk.probability)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.corpus -> nltk.tokenize -> nltk.tokenize.texttiling)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.draw.tree -> nltk.tree)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.tree -> nltk.treeprettyprinter)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.grammar -> nltk.parse.pchart)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.stem -> nltk.stem.porter)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.classify.maxent -> nltk.classify.tadm)
完整列表在https://github.com/nltk/nltk/issues/2113
但看看进口：
from __future__ import unicode_literals from
import re
from collections import defaultdict
from nltk.ccg.api import PrimitiveCategory, Direction, CCGVar, FunctionalCategory
from nltk.compat import python_2_unicode_compatible
from nltk.internals import deprecated
from nltk.sem.logic import *
但是看看nltk.internals https://github.com/nltk/nltk/blob/develop/nltk/internals.py，没有任何循环导入指向nltk.ccg.lexicon：
from __future__ import print_function
import subprocess
import os
import fnmatch
import re
import warnings
import textwrap
import types
import sys
import stat
import locale
# Use the c version of ElementTree, which is faster, if possible:
try:
from xml.etree import cElementTree as ElementTree
except ImportError:
from xml.etree import ElementTree
from six import string_types
from nltk import __file__
from nltk import compat
消息是什么R0401(cyclic-import)意思？
查看nltk.ccg.lexicon.pyandnltk.internals.py没有任何循环的导入，那么如何解决问题。