slice() object in Python

Question

import numpy as np
letters = np.array([1, 3, 5, 7, 9, 7, 5])
print(letters[0:5:2])
print(letters[slice(letters[0,5,2])])

OUTPUT:
[1 5 9]
( IndexError: too many indices for array)

Why is this error coming ? I have seen on internet that both these notations works similarly.

Answer 1

print(letters[slice(0, 5, 2)])

or

s = slice(0, 5, 2)
print(letters[s])