>>> import heapq
>>> heap = []
>>> heapq.heappush(heap, 1)
>>> heapq.heappush(heap, 3)
>>> heapq.heappush(heap, 5)
>>> heapq.heappush(heap, 2)
>>> heapq.heappush(heap, 4)
>>> heapq.nsmallest(3, heap)
[1, 2, 3]

>>> import functools
>>> import heapq
>>> heap = []
>>> push = functools.partial(heapq.heappush, heap)
>>> smallest = functools.partial(heapq.nsmallest, iterable=heap)

>>> push(1)
>>> push(3)
>>> push(5)
>>> push(2)
>>> push(4)
>>> smallest(3)
[1, 2, 3]