human
Solve the following python programming problem given the following code:
def countBy(self, val) : 
    '
        Counts instances of an object that group by a certain criterion. Pass
        either a string attribute to count by, or a function that returns the
        criterion.
        ' 
    def by(result, key, value) : 
        if (key not in result) : 
            result [key] = 0 
result [key] += 1 
res = self._group (self.obj, val, val) 
    return self._wrap (res) 

    
    

    Fix the buggy line: res = self._group (self.obj, val, val)
assistant
#Here is Python program to fix the buggy line: res = self.

res = self._group (self.obj, val, def by()