Peeking in a heap in python
Yes, you can make this assumption, because it is stated in the documentation:
Heaps are arrays for which
heap[k] <= heap[2*k+1]andheap[k] <= heap[2*k+2]for all k, counting elements from zero. For the sake of comparison, non-existing elements are considered to be infinite. The interesting property of a heap is thatheap[0]is always its smallest element.
(And that's probably the reason there is no peek function: there is no need for it.)