下記のようなコードに対し、エラーが出ましたこれはどういうエラーでしょうか？
参考：tensor flow始めました

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import os

import numpy as np
import tensorflow as tf
from PIL import Image
from reader import Cifar10Reader

FLAGS = tf.app.flags.FLAGS
tf.app.flags.DEFINE_string('file', None, "処理するファイルのパス")
tf.app.flags.DEFINE_integer('offset', 0, "読み飛ばすレコード数")
tf.app.flags.DEFINE_integer('length', 16, "読み込んで変換するレコード数")

baseename = os.path.basename(FLAGS.file)
path = os.path.dirname(FLAGS.file)

reader = Cifar10Reader(FLAGS.file)

stop =FLAGS.offset + FLAGS.length
for index in range(FLAGS.offset, stop):
    image = reader.red(index)

    print('label: %d' % image.label)
    imageshow = Image.formarray(image.byte_array.astype(np.uint8))

    file_name = '%s-%02d-%d.png' % (basename, index, image.label)
    fole = os.path.join(path, file_name)
    with open(file, mode='wb') as out:
        imageshow.save(out, format='png')


reader.close()    

---

ArgumentError                             Traceback (most recent call last)
<ipython-input-18-9a5ff25e4587> in <module>()
      1 FLAGS = tf.app.flags.FLAGS
----> 2 tf.app.flags.DEFINE_string('file', None, "処理するファイルのパス")
      3 tf.app.flags.DEFINE_integer('offset', 0, "読み飛ばすレコード数")
      4 tf.app.flags.DEFINE_integer('length', 16, "読み込んで変換するレコード数")
      5 

~/anaconda/envs/tensorflow/lib/python3.5/site-packages/tensorflow/python/platform/flags.py in DEFINE_string(flag_name, default_value, docstring)
     78     docstring: A helpful message explaining the use of the flag.
     79   """
---> 80   _define_helper(flag_name, default_value, docstring, str)
     81 
     82 

~/anaconda/envs/tensorflow/lib/python3.5/site-packages/tensorflow/python/platform/flags.py in _define_helper(flag_name, default_value, docstring, flagtype)
     63                               default=default_value,
     64                               help=docstring,
---> 65                               type=flagtype)
     66 
     67 

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in add_argument(self, *args, **kwargs)
   1342                 raise ValueError("length of metavar tuple does not match nargs")
   1343 
-> 1344         return self._add_action(action)
   1345 
   1346     def add_argument_group(self, *args, **kwargs):

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in _add_action(self, action)
   1705     def _add_action(self, action):
   1706         if action.option_strings:
-> 1707             self._optionals._add_action(action)
   1708         else:
   1709             self._positionals._add_action(action)

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in _add_action(self, action)
   1546 
   1547     def _add_action(self, action):
-> 1548         action = super(_ArgumentGroup, self)._add_action(action)
   1549         self._group_actions.append(action)
   1550         return action

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in _add_action(self, action)
   1356     def _add_action(self, action):
   1357         # resolve any conflicts
-> 1358         self._check_conflict(action)
   1359 
   1360         # add to actions list

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in _check_conflict(self, action)
   1495         if confl_optionals:
   1496             conflict_handler = self._get_handler()
-> 1497             conflict_handler(action, confl_optionals)
   1498 
   1499     def _handle_conflict_error(self, action, conflicting_actions):

~/anaconda/envs/tensorflow/lib/python3.5/argparse.py in _handle_conflict_error(self, action, conflicting_actions)
   1504                                      for option_string, action
   1505                                      in conflicting_actions])
-> 1506         raise ArgumentError(action, message % conflict_string)
   1507 
   1508     def _handle_conflict_resolve(self, action, conflicting_actions):

ArgumentError: argument --file: conflicting option string: --file