def guess():
while True:
try:
guess = raw_input("Guess your letter")
if len(guess) != 1 or guess.isdigit() == True:
print "Please guess again"
if len(guess) == 1 and guess.isdigit() == False:
guessed.append = guess
return guess
break
except StandardError:
pass
print guess()
无论我在原始输入中输入什么值,这个循环都会不断重复。为什么???