bad argument type for built-in operation

[Florian Lindner]

Hello,
I've the traceback:

Traceback (most recent call last):
File "visualizer.py", line 8, in ?
main()
File "visualizer.py", line 5, in main
g = GraphCreator(f)
File "/home/florian/visualizer/GraphCreator.py", line 13, in __init__
self.conf = ConfigReader(config)
File "/home/florian/visualizer/ConfigReader.py", line 53, in __init__
graph.sourceReader = CSVReader(filename, firstline, delimiter)
File "/home/florian/visualizer/ConfigReader.py", line 13, in __init__
self.reader = csv.reader(f, delimiter=Adelimiter)
TypeError: bad argument type for built-in operation

f ist file object, Adelimiter is ",".

What is wrong there?

Thanks,
Florian