方法一：
import string
count = 8
str_from = string.ascii_letters + string.digits "".join([random.choice(str_from) for _ in range(count)])
方法二：
import string
str_from = string.ascii_letters + string.digits
tokens = []
count = 10
for i in range(count):
s = random.choice(str_from)
# print(s)
tokens.append(s)
"".join(tokens)