Not all methods of MinMaxHeap which accept indices assert that indices are in the bounds

[nbro]

For consistency, I should assert in all methods that accept "indices" that they are valid, i.e. by using something of the form assert self.is_good_index(my_index). Examples of functions that do not do that: _index_of_max, _index_of_min, etc.

Mare sure that this assertion is required in certain methods: it may happen that it's "ok" that in a call or recursive sub-call to a function the indices are no more valid!!!

Check also the cases for BinaryHeap, MinHeap and MaxHeap.

[nbro]

False positive: those functions are already checking their indices when they call other functions at the beginning of their body which actually explicitly call assert self.is_good_index(my_index).