2. 完成字符串“吃葡萄不吐葡萄皮，不吃葡萄到吐葡萄皮”中“葡”字的个数，以count.py保存。

count = 0
str = "吃葡萄不吐葡萄皮，不吃葡萄到吐葡萄皮"
for i in str:
if i == "葡":
count += 1
with open("count.py", "w") as f:
f.write("count = {}".format(count))