Need Help with an Antivirus script in py3

[nilamo]

Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) [MSC v.1900 32 bit (Intel)] on win32
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>>> def scan(pathname, signatures, depth):
...     for item in os.listdir(pathname) and depth > 0:
...         n = os.path.join(pathname, item)
...         try:
...             scan(n, signatures, depth-1)
...         except:
...             f = open(n, 'r')
...             s = f.read()
...             for virus in signatures:
...                 if s.find(signatures[virus]) > 0:
...                     print('{}, found virus {}'.format(n,virus))
...             f.close()
...
>>>

Works fine for me. Please show the whole error, and probably more of your actual script. Otherwise, we're just taking wild guesses.