Underscores in Python numbers

[Roy Smith]

Mike Meyer <mwm at mired.org> wrote:
> I've seen at least one language (forget which one) that allowed such
> separators, but only for groups of three.

That seems a bit silly.  Not all numbers are naturally split into groups of 
three.  Credit card numbers are (typically) split into groups of four.  
Account numbers are often split into all sorts of random groupings.