human
Solve the following python programming problem given the following code:
@ pytest.fixture (scope = 'function') 
def remove_output_folder(request) : 
    '
    Remove the output folder in case it exists on disk.
    ' 
    def finalizer_remove_output_folder() : 
        if os.path.exists ('output_folder') : 
            utils.rmtree ('output_folder') 
request.addfinalizer (<MASK>) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def finalizer_remove_output_folder(