Extendleft() method in Python

import collections

multiples       = (0, -10, -20)

# Create a deque instance from a tuple of two elements

dequeInstance   = collections.deque((10, 20))

print("Initial deque:")

print(dequeInstance)

# Extend the deque on the left side using a tuple

print("Deque after exetending it on the left side:")

dequeInstance.extendleft(multiples)

print(dequeInstance)

Initial deque:

deque([10, 20])

Deque after exetending it on the left side:

deque([-20, -10, 0, 10, 20])