python fromkeys 方法
fromkeys(seq,b) 方法用于创建一个新字典,以 seq 中元素作为key值,b作为字典中键对应的value
seq = ('Google', 'Runoob', 'Taobao') this=dict.fromkeys(seq) this {'Google': None, 'Runoob': None, 'Taobao': None} this=dict.fromkeys(seq,10) this {'Google': 10, 'Runoob': 10, 'Taobao': 10}