Py文件错误IndentationError：预期缩进块

Question

import sys
sys.path.append('..')
from mmfparser.data.exe import ExecutableData
from mmfparser.data.gamedata import GameData
from mmfparser.data.mfa import MFA
from mmfparser.translators.pame2mfa import translate
from mmfparser.bytereader import ByteReader
import sys
import os
def main():
print 'welcome'
print 'prepare your duckshells'
print ''
input = sys.argv[1]
output = sys.argv[2]
fp = ByteReader(open(input, 'rb'))
if input.endswith('.ccn'):
newGame = GameData(fp)
else:
newExe = ExecutableData(fp)
for file in newExe.packData.items:
name = file.filename.split('\\')[-1]
print 'Writing pack file %r' % name
open(os.path.join(output, name), 'wb').write(file.data)
newGame = newExe.gameData
if newGame.files is not None:
for file in newGame.files.items:
name = file.name.split('\\')[-1]
print 'Writing embedded file %r' % name
open(os.path.join(output, name), 'wb').write(str(file.data))
newGame.files = None
def out(value):
print value
newMfa = translate(newGame, print_func = out)
out_path = os.path.join(output, 'out.mfa')
newMfa.write(ByteReader(open(out_path, 'wb')))
# newMfa = MFA(ByteReader(open(out_path, 'rb')))
print 'Finished!'
if __name__ == '__main__':
main()

我收到错误IndentationError：打开时会出现缩进块？有什么建议？它是从2012年开始的。我使用的是python 2.7，它是MultiMedia Fusion的反编译器