In Python a Boolean true and false are often used in mathematical formulas, so they will often implicitly be coerced into the integers 1 and 0. Sum is the sum f

In Python a Boolean true and false are often used in mathematical formulas, so they will often implicitly be coerced into the integers 1 and 0. Sum is the sum function, you can sum a sequence of numbers, but in this case it’s summing a bunch of Boolean values which are coerced to 1 and 0.