@staticmethod
def _decrease_pool_count(pool_list, pool, count=1):
    """Decrement pool's size by count.

        If pool becomes empty, remove pool from pool_list.
        """
    if pool['count'] > count:
        pool['count'] -= count
        count = 0
    else:
        count -= pool['count']
        pool_list.remove(pool)
    return count
