Human: index of largest value of array. Assistant: 
Here is a Python function to index the largest value of an array

import numpy as np

def largest_index(array):
    """
    Returns the index of the largest value in the array.
    """
    return np.argmax(array)

# Enter the array
array = np.array([1, 2, 3, 4, 5])

# Calling the function
print((largest_index(array)))

#Remember to inspect code for bugs.