in-not-in.py

# coding: UTF-8

nums = [1, 2, 3, 4, 5]

# in: 存在確認
print(2 in nums) # True
print(6 in nums) # False

# not in: 非存在確認
print(2 not in nums) # False
print(6 not in nums) # True

# 関数ではなく演算子