A tuple is a group of references to different items. These references or locations in memory are immutable, but the items these references point to could be mutable - lists - or immutable - strings -.

Sometimes the mutable elements in a tuple could create hard-to-find errors. 

We could use a hash function to check the "complete" immutability of a tuple as below:

Regarding the output, we get:

False : because "t1" contains a mutable item - list -.