如何在python中找到字符串中的子字符串的出现次数？

def count_substring(string, substring):
    return string.count(substring)

# 示例用法
string = "Hello, World! Hello, Python!"
substring = "Hello"
count = count_substring(string, substring)
print(f"The substring '{substring}' appears {count} times in the string.")

The substring 'Hello' appears 2 times in the string.