"is" is for asking whether two objects are the same exact object in memory. "==" is for asking whether two objects are logically equal, ie, that they represent the same value. As an example:

    >>> x = [1,2,3]
    >>> y = [1,2,3]
    >>> x == y
    True        # two lists with the same values; equal
    >>> x is y
    False       # two different lists; doesn't matter that they contain the same values
    >>> z = x
    >>> z is x
    True        # same list object in memory

Because here you want to know if the two integers are logically equal, not if they're necessarily the same object in memory, you want "==" and not "is". Due to an optimisation, "is" might work for small integers, depending on implementation, but the takeaway is not to use "is" for value comparisons; that's what "==" is for.