Bollinger Bands Width Expansion Identifier

Find out if the Bollinger Band Width has rapidly expanded compared to the N number of previous periods.

I've written a function: 'bbw_expansion' that performs this check so that it can be incorporated in other projects of mine.

Example: bbw_expansion(bbw, 5, 1.2) will return 'true' if 'bbw' is 20% greater (or more) compared to the last 5 bbw periods.

The function returns: 'true' or 'false'