# Chain `is` Published: 2022-09-27. A long time ago, we already covered the chaining of comparison operations: A quick summary is that the result of right value from each comparison gets passed into the next one: ```python 13 > 2 > 1 # same as `13 > 2 and 2 > 1` # True 13 > 2 > 3 # same as `13 > 2 and 2 > 3` # False ``` What's interesting, is that `is` and `in` are also considered to be operators, and so can be also chained, which can lead to unexpected results: ```python a = None a is None # True, as expected a is None is True # False 🤔 a is None == True # False 🤔 a is None is None # True 🤯 ``` The best practice is to use the operator chaining only to check if the value in a range using `<` and `<=`: ```python teenager = 13 < age < 19 ```