human
Solve the following python programming problem given the following code:
def test_command_decorator(self) : 
    '
        @Application.command decorator should register a command
        ' 
    application = Application () 
    @ application.command ('decorated_foo', description = 'Foo') 
    def decorated_foo_code(i, o) : 
        o.writeln ('called') 
self.assertTrue (application.has ('decorated_foo')) 
    command = application.get ('decorated_foo') 
    self.assertEqual (command._code, <MASK>) 
    self.assertEqual (command.get_description (), 'Foo') 
    self.assertTrue (('decorated_foo_code' in command.get_aliases ())) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def decorated_foo_code(