How to implement negative infinity in Python?

I am trying to implement a Heap defined Priority Queue, the algorithm is from CLRS book chapter 6. The pseudocode is listed below:

Max_Heap_Insert(A, key):
    A.heap_size = A.heap_size + 1
    A[A.heap_size] = -∞
    Heap_Increase_Key(A, A.heap_size, key)

My question is that using python, how do I define -∞?

Python has special values float('inf') and float('-inf').