Python 如何纠正返回字符串中子字符串数的代码？

我想制作一个程序，计算字符串中给定子字符串的数量

s = 'azcbobobegghakl'
substring = "bob"

for i in range(0, len(s)):
    if substring in s:
        j = 0
        count = 0
        count1 = 0
        while s[i] == substring[j]:
            count += 1
            i += 1
            j += 1
            if j > len(substring):
                break
        if count == len(substring):
            count1 += 1
            count = 0
        else:
            i += 1

print(count1)

输出：

2

2