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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def PathList(self, pathlist):
 """ Returns the cached _PathList object for the specified pathlist, creating and caching a new object as necessary. """

        pathlist = self._PathList_key(pathlist)
        try:
            memo_dict = self._memo['PathList']
        except KeyError:
            memo_dict = {}
            self._memo['PathList'] = memo_dict
        else:
            try:
                return memo_dict[pathlist]
            except KeyError:
                pass

        result = _PathList(pathlist)

        memo_dict[pathlist] = result

        return result