Error in file opening Vizard

[Vishav]

Dear all,

I am getting this error in my code when i am opening file in append mode:

Traceback (most recent call last):
File "C:\Program Files\WorldViz\Vizard5\python\viztask.py", line 752, in updateAndKillOnException
return self.update()
File "C:\Program Files\WorldViz\Vizard5\python\viztask.py", line 719, in update
val = self._stack[-1].send(sendData)
File "DFI_Snacks.py", line 50, in task1
IOError: [Errno 22] invalid mode ('a') or filename: '<built-in function id>_experiment_data.txt'

My Source Code:


global experiment_data
os.chdir(r'D:\PhD\Study-I_Part_I\My_Programs\DFI\Participant_Data')
filename=str(id) +'_experiment_data.txt'
experiment_data = open(filename,'a')
print str(id)
I am getting exporting id value from other code

Please help me in it.
Thanks