If n is an integer, n << 8 is equivalent to n * (2**8). The << operator is called the left shift operator. It comes from the binary representation of integers, for example 6 is represented as 110 in binary form, and 6 << 3 as 110000. Other languages use the same convention (in particular the C language, the mother of so many languages).
In python there is no theoretical limit to the size of integers, so that you can write 6 << 1000 and still obtain 6 * 2 ** 1000. This wouldn't work in languages where integers are limited to 32 bits or 64 bits.
Another feature of python is that the binary operator << can be overloaded and have an arbitrary different meaning for user defined data types.