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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 _setupCache(self):
 """ Setup the cache based on the provided values for localCacheDir. """

        # we first check whether the cache directory exists. If it doesn't, create it.
        if not os.path.exists(self.localCacheDir):
            # Create a temporary directory as this worker's private cache. If all goes well, it
            # will be renamed into the cache for this node.
            personalCacheDir = ''.join([os.path.dirname(self.localCacheDir), '/.ctmp-',
                                        str(uuid.uuid4())])
            os.mkdir(personalCacheDir, 0o755)
            self._createCacheLockFile(personalCacheDir)
            try:
                os.rename(personalCacheDir, self.localCacheDir)
            except OSError as err:
                # The only acceptable FAIL case is that the destination is a non-empty directory
                # directory.  Assuming (it's ambiguous) atomic renaming of directories, if the
                # dst is non-empty, it only means that another worker has beaten this one to the
                # rename.
                if err.errno == errno.ENOTEMPTY:
                    # Cleanup your own mess.  It's only polite.
                    shutil.rmtree(personalCacheDir)
                else:
                    raise
        # You can't reach here unless a local cache directory has been created successfully
        with self._CacheState.open(self) as cacheInfo:
            # Ensure this cache is from the correct attempt at the workflow!  If it isn't, we
            # need to reset the cache lock file
            if cacheInfo.attemptNumber != self.workflowAttemptNumber:
                if cacheInfo.nlink == 2:
                    cacheInfo.cached = 0  # cached file sizes are accounted for by job store
                else:
                    allCachedFiles = [os.path.join(self.localCacheDir, x)
                                      for x in os.listdir(self.localCacheDir)
                                      if not self._isHidden(x)]
                    cacheInfo.cached = sum([os.stat(cachedFile).st_size
                                            for cachedFile in allCachedFiles])
                    # TODO: Delete the working directories
                cacheInfo.sigmaJob = 0
                cacheInfo.attemptNumber = self.workflowAttemptNumber
            self.nlinkThreshold = cacheInfo.nlink