Python_字典包含关系判定方法

a = {"a": 1, "b": 2, "c": 3, "d": 4}
b = {"b": 2, "c": 3}
c = {"a": 2, "b": 2}
print(a.viewitems())
print(b.viewitems() <= a.viewitems())
print(c.viewitems() <= a.viewitems())