题解 | #字典新增#

import sys
dictionary = {'a': ['apple', 'abandon', 'ant'], 'b': ['banana', 'bee', 'become'], 'c': ['cat', 'come'], 'd': 'down'}
letter = input()
word = input()

if letter in dictionary:
    value = dictionary[letter]
    if type(value) == list:
        words = list(value)
    else:
        words = list((value,))

    words.append(word)
    dictionary.update({letter:words})
else:       
    dictionary.update({letter:word})

print(dictionary)