human
Solve the following python programming problem given the following code:
def test_argument_decorator(self) : 
    '
        @Application.argument decorator should register a command with a specific argument
        ' 
    application = Application () 
    @ application.argument ('foo', description = 'Foo', required = True, is_list = True) 
    def decorated_foo_code(i, o) : 
        'Foo Description' 
        o.writeln ('called') 
self.assertTrue (application.has ('decorated_foo_code')) 
    command = application.get ('decorated_foo_code') 
    self.assertEqual (command._code, <MASK>) 
    self.assertEqual (command.get_description (), 'Foo Description') 
    argument = command.get_definition ().get_argument ('foo') 
    self.assertEqual ('Foo', argument.get_description ()) 
    self.assertTrue (argument.is_required ()) 
    self.assertTrue (argument.is_list ()) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: self, argument, command, application
assistant
#Here is a proper replacement for <MASK>.
def decorated_foo_code(