A class that extends the immutable tuple

NumberTuple.py

class NumberTuple(tuple):
    '''
    NumberTuple is a tuple class that wishes to convert
    string number to a tuple.
    '''
    
    def __init__(self, number):
        '''
        While our goal is to convert the string number
        to a tuple, we cannot reassign the NumberTuple object
        in the __init__ function - since it's already been created,
        and it's immutable.
        '''
        pass

    def __new__(cls, number):
        '''
        This is where __new__ comes to the rescue: this is invoked
        before the tuple object is created. We interject, converting
        the number from a string to a tuple, and then finally
        tell python to use the tuple value we created!
        '''
        if isinstance(number, str):
            number = tuple(number)
        return super(NumberTuple, cls).__new__(cls, number)

# output: ('1', '2', '4' )
print(NumberTuple('124'))