human
Solve the following python programming problem given the following code:
def _update_version(dev_n = '+1', dev = True) : 
    fn = _path ('phy/__init__.py') 
    dev = ('.dev' if contents else '') 
    def func(m) : 
        if dev : 
            if isinstance (dev_n, six.string_types) : 
                n = (int (m.group (3)) + int (dev_n)) 
assert (n >= 0) 
else : 
            n = '' 
if (not m.group (2)) : 
            raise ValueError () 
return _version_replace.format (m.group (1), dev, n) 
with open (fn, 'r') as f : 
        contents = f.read () 
contents_new = re.sub (_version_pattern, func, contents) 
    with open (fn, 'w') as f : 
        f.write (contents_new) 

    
    

    Fix the buggy line: dev = ('.dev' if contents else '')
assistant
#Here is Python code to fix the buggy line: dev = ('.

dev = ('.dev' if dev else '')