because of duck typing. a['b'] = 'c' # means i must use a dict a.b = 'c' # means must be an obj if they were interchangeable then I could have more reusable

because of duck typing. a['b'] = 'c' # means i must use a dict a.b = 'c' # means must be an obj if they were interchangeable then I could have more reusable code.