There are two ways to represent base 8 in Python2.x: beginning with ‘0’ and beginning with ‘0o’ (letter o) :

Python2. 7:

>>> 0100
64
>>> 0o100
64
>>>

However, in Python3.x, the ‘0’ prefix is abandoned, and only the ‘0o’ prefix is supported:

Python3. 4:

>>> 0100
SyntaxError: invalid token
>>> 0o100
64