Function get_random_item 

pub fn get_random_item<'a, T, R: Random>(
    random: &mut R,
    items: &'a [T],
    weight: impl Fn(&T) -> i32,
) -> Option<&'a T>

Picks an entry with probability proportional to its weight. A zero total weight returns None without consuming random values.

Panics

Panics if the total weight is negative.