4.2-4 デフォルトのオブジェクト
print(int())
->0
print(float())
->0.0
print(bool())
->False
print(str())
->''
print(list())
->[]
print(tuple())
->()
print(dict())
->{}
print(set())
->set()
print(int())
->0
print(float())
->0.0
print(bool())
->False
print(str())
->''
print(list())
->[]
print(tuple())
->()
print(dict())
->{}
print(set())
->set()