Off topic:opening a file wih a function in python

Question

[sven.lemoinebauer]

Hey everybody, probably stupid question, but I do not understand what is wrong there, I guess I just do not know how to properly open a file in a function. Having my csv file in the folder, I want to make a list out of the it:

def make_OTU_list(csvfile):
    with open(csvfile, "rb") as list_input:
        csv = csv.reader(list_input)
        list_OTU = list(csv)[0]
        return list_OTU

make_OTU_list("OTU95_dominating.csv")

and I come back with that:

Traceback (most recent call last):
  File "labbook.py", line 35, in <module>
    make_OTU_list("OTU95_dominating.csv")
  File "labbook.py", line 31, in make_OTU_list
    csv = csv.reader(list_input)
UnboundLocalError: local variable 'csv' referenced before assignment

Can somebody solve my problem? Thanks a lot!