Assertion error when checking if a MinMaxHeap is a MinMaxHeap inside the deletion operation

[nbro]

When I was running all tests locally, using the script ./run_tests.sh, at a certain point, an assertion (i.e. assert is_min_max_heap(self)) in the deletion operation was not satisfied. This only occurred locally and when I run all tests, apparently.

In general, there was some strange behavior going on.

Verify that the algorithm for deleting an element from a MinMaxHeap (and also MaxHeap and MinHeap) really work, but thinking about all possible cases!!!

[nbro]

The bug was apparently in the function is_min_max_heap (and not in the delete method of MinMaxHeap).