nvts = {"high": [], "medium": [], "low": [], "log": []}

for a, *b in nvts:print(a, ' '.join(map(str, b)))

h i g hm e di u m ...

nvts = {"high": [], 


 "medium": ["value1"], 


 "low": ["value 2","value 3"], 


 "log": ["more value", "even more value"]}



print("n".join([item for sublist in nvts.values() for item in sublist]))

输出：

value1


value 2


value 3


more value


even more value

如果只想打印key：

print("n".join(nvts.keys()))

输出

high


medium


low


log