Complete the code which should return `true` if the given object is a single ASCII letter (lower or upper case), `false` otherwise.

Difficulty: introductory

Starter code:

def is_letter(s):
	

Solutions:
def is_letter(s):
    return len(s) == 1 and s.isalpha()

import re

def is_letter(stg):
    return bool(re.match(r"[a-z]\Z", stg, re.I))

import re
def is_letter(s):
    return bool(re.fullmatch("[A-Za-z]",s))

is_letter=lambda s:(s==s[-1:])&s.isalpha()

import re
def is_letter(s):
    return re.match(r'(?i)[a-z]\Z', s) is not None

import re
def is_letter(s):
    return bool(re.match(r'^[a-z]$',re.escape(s), re.I))

def is_letter(s):
    
    return (s ==s[-1:]) and s.isalpha()

def is_letter(char):
    return char.isalpha() and len(char) == 1

def is_letter(s):    
    return s.isalpha() and len(s)==1

import re

def is_letter(s):
    return bool(re.fullmatch(r"[a-zA-Z]", s))