Write a Python program to test whether a passed letter is a vowel or not

Introduction

Write a Python program to test whether a passed letter is a vowel or not. I have used python 3.7 compiler for debugging purpose.

def is_vowel(char):
    all_vowels = 'aeiou'
    return char in all_vowels
print(is_vowel('e'))
print(is_vowel('z'))