human
Solve the following python programming problem given the following code:
@ extensionmethod (Observable) 
def group_join(self, right, left_duration_selector, right_duration_selector, result_selector) : 
    "Correlates the elements of two sequences based on overlapping
    durations, and groups the results.

    Keyword arguments:
    right -- The right observable sequence to join elements for.
    left_duration_selector -- A function to select the duration (expressed
        as an observable sequence) of each element of the left observable
        sequence, used to determine overlap.
    right_duration_selector -- A function to select the duration (expressed
        as an observable sequence) of each element of the right observable
        sequence, used to determine overlap.
    result_selector -- A function invoked to compute a result element for
        any element of the left sequence with overlapping elements from the
        right observable sequence. The first parameter passed to the
        function is an element of the left sequence. The second parameter
        passed to the function is an observable sequence with elements from
        the right sequence that overlap with the left sequence's element.

    Returns an observable sequence that contains result elements computed
    from source elements that have an overlapping duration.
    " 
    left = self 
    def subscribe(observer) : 
        nothing = (lambda _ : None) 
        group = CompositeDisposable () 
        r = RefCountDisposable (group) 
        left_map = OrderedDict () 
        right_map = OrderedDict () 
        left_id = [0] 
        right_id = [0] 
        def on_next_left(value) : 
            s = Subject () 
            with self.lock : 
                _id = left_id [0] 
                left_id [0] += 1 
                left_map [_id] = s 
try : 
                result = result_selector (value, add_ref (s, r)) 
except Exception as e : 
                log.error (('*** Exception: %s' % e)) 
                for left_value in left_map.values () : 
                    left_value.on_error (e)...

    
    

    Fix the buggy line: return AnonymousObservable (right)
assistant
#Here is Python program to determine overlap.

return AnonymousObservable (subscribe)