def biggest(aDict):
    '''
    aDict: A dictionary, where all the values are lists.
 
    returns: The key with the largest number of values associated with it
    '''
    maior = 0
    chave_maior = None
    for chave, valor in aDict.items():
        if len(valor) > maior:
            maior = len(valor)
            chave_maior = chave
 
    return chave_maior
 
 
animals = { 'a': ['aardvark'], 'b': ['baboon'], 'c': ['coati']}
 
animals['d'] = ['donkey']
animals['d'].append('dog')
animals['d'].append('dingo')
 
 
print(biggest(animals))

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