参考代码：

def binary_search(data, item):
    n = len(data)
    if n > 0:
        mid = n // 2
        if data[mid] == item:
            return True
        elif data[mid] > item:
            return binary_search(data[:mid], item)
        else:
            return binary_search(data[mid+1:], item)
    return False