human
Solve the following python programming problem given the following code:
def _bundle_fixtures(self, test) : 
    "Reorder the tests in the suite so classes using identical
        sets of fixtures are contiguous.

        I reorder FastFixtureTestCases so ones using identical sets
        of fixtures run adjacently. I then put attributes on them
        to advise them to not reload the fixtures for each class.

        This takes support.mozilla.com's suite from 123s down to 94s.

        FastFixtureTestCases are the only ones we care about, because
        nobody else, in practice, pays attention to the ``_fb`` advisory
        bits. We return those first, then any remaining tests in the
        order they were received.

        " 
    def suite_sorted_by_fixtures(suite) : 
        'Flatten and sort a tree of Suites by the ``fixtures`` members of
            their contexts.

            Add ``_fb_should_setup_fixtures`` and
            ``_fb_should_teardown_fixtures`` attrs to each test class to advise
            it whether to set up or tear down (respectively) the fixtures.

            Return a Suite.

            ' 
        bucketer = Bucketer () 
        process_tests (suite, bucketer.add) 
        flattened = [] 
        for ((fixtures, is_exempt), fixture_bundle) in bucketer.buckets.items () : 
            if (fixtures and (not is_exempt)) : 
                first = fixture_bundle [0].context 
                first._fb_should_setup_fixtures = True 
                for cls in fixture_bundle [1 :] : 
                    cls.context._fb_should_setup_fixtures = False 
last = fixture_bundle [(- 1)].context 
                last._fb_should_teardown_fixtures = True 
                for cls in fixture_bundle [: (- 1)] : 
                    cls.context._fb_should_teardown_fixtures = False 
flattened.extend (fixture_bundle) 
flattened.extend (bucketer.remainder) 
        return ContextSuite (flattened) 
return suite_sorted_by_fixtures (suite_sorted_by_fixtures) 

    
    

    Fix the buggy line: return suite_sorted_by_fixtures (suite_sorted_by_fixtures)
assistant
#Here is Python program to fix the buggy line: return suite_sorted_by_fixtures (suite_sorted_by_fixtures)
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return suite_sorted_by_fixtures (test)