Implement the function which should return `true` if given object is a vowel (meaning `a, e, i, o, u`), and `false` otherwise.

Difficulty: introductory

Starter code:

def is_vowel(s):
	

Solutions:
def is_vowel(s):
    return s.lower() in set("aeiou")

import re
def is_vowel(s): 
    regex = r'^[aeiou]{1}$'
    return bool(re.match(regex, re.escape(s), re.IGNORECASE))

import re

def is_vowel(stg): 
    return bool(re.fullmatch(r"[aeiou]", stg, re.I))

def is_vowel(s): 
    return True if s.lower() in ['a', 'e', 'i', 'u', 'o'] else False

is_vowel = set("aeiouAEIOU").__contains__

import re

def is_vowel(s):
    return True if re.match(r"^[AaEeIiOoUu](?!\n)$", s) else False

def is_vowel(s): 
    return bool(s) and s.lower() in 'uaeio'

import re
PATTERN = re.compile('[eaiou]', flags=re.I)
def is_vowel(s): 
    return bool(PATTERN.fullmatch(s))

import re

def is_vowel(string):
    return bool(re.match('^[aeiou]\Z', string, re.IGNORECASE))

import re
def is_vowel(s): 
    if len(s) == 1:
        if s[0] in "a e i o u A E I O U".split():
            return True
    return False