Check whether an integer is a power of two in Python

To check whether an integer is a power of two, I've deployed hacks like this:

While this hex trick works, I've never liked explaining the pattern matching hack that's going on here.

Today, I came across this tweet by Raymond Hettinger where he proposed an elegant solution to the problem. Here's how it goes:

This is neat as there's no hack and it uses a mathematical invariant to check whether an integer is a power of 2 or not. Also, it's a tad bit faster.

Explanation

Any integer that's a power of 2, will only contain a single 1 in its binary representation.

For example:

The .bit_count() function checks how many on-bits (1) are there in the binary representation of an integer.

Complete example with tests