Python -对字典中的值进行分组

def group_by_value(dictionary):
    groups = {}
    for key, value in dictionary.items():
        if value not in groups:
            groups[value] = [key]
        else:
            groups[value].append(key)
    return groups

my_dict = {'apple': 'fruit', 'carrot': 'vegetable', 'banana': 'fruit', 'spinach': 'vegetable'}
result = group_by_value(my_dict)
print(result)

{'fruit': ['apple', 'banana'], 'vegetable': ['carrot', 'spinach']}