如何在字符串中搜索子字符串，然后在python中查找子字符串之前的字符

string = "Hello, World!"
substring = "World"

index = string.find(substring)
if index != -1:
    before_substring = string[:index]
    print(before_substring)
else:
    print("Substring not found")

string = "Hello, World!"
substring = "World"

try:
    index = string.index(substring)
    before_substring = string[:index]
    print(before_substring)
except ValueError:
    print("Substring not found")