如何获取配置单元中的子字符串计数

def count_substring(config_unit, substring):
    count = 0
    index = 0
    while index < len(config_unit):
        index = config_unit.find(substring, index)
        if index == -1:
            break
        count += 1
        index += len(substring)
    return count

# 示例用法
config_unit = "This is a sample configuration unit. It contains multiple instances of the word 'sample'."
substring = "sample"
result = count_substring(config_unit, substring)
print("子字符串 '{}' 在配置单元中出现的次数为: {}".format(substring, result))