'Decrement pool\'s size by count.
If pool becomes empty, remove pool from pool_list.'

@staticmethod
def _decrease_pool_count(pool_list, pool, count=1):

    if (pool['count'] > count):
        pool['count'] -= count
        count = 0
    else:
        count -= pool['count']
        pool_list.remove(pool)
    return count
