human
Solve the following python programming problem given the following code:
def _apply_window(self, mean = True, how = None, **kwargs) : 
    '
        Applies a moving window of type ``window_type`` on the data.

        Parameters
        ----------
        mean : boolean, default True
            If True computes weighted mean, else weighted sum
        how : string, default to None (DEPRECATED)
            how to resample

        Returns
        -------
        y : type of input argument

        ' 
    window = self._prep_window (** kwargs) 
    center = self.center 
    (blocks, obj) = self._create_blocks (how = how) 
    results = [] 
    for b in blocks : 
        try : 
            values = self._prep_values (b.values) 
except TypeError : 
            results.append (b.values.copy ()) 
            continue 
if (values.size == 0) : 
            results.append (values.copy ()) 
            continue 
offset = _offset (mean, center) 
        additional_nans = np.array (([np.NaN] * offset)) 
        def f(arg, * args, **kwargs) : 
            minp = _use_window (self.min_periods, len (window)) 
            return algos.roll_window ((np.concatenate ((arg, additional_nans)) if center else arg), window, minp, avg = mean) 
result = np.apply_along_axis (f, self.axis, values) 
        if center : 
            result = self._center_window (result, window) 
results.append (result) 
return self._wrap_results (results, blocks, obj) 

    
    

    Fix the buggy line: offset = _offset (mean, center)
assistant
#Here is Python code to fix the buggy line: offset = _offset (mean, center)
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offset = _offset (window, center)