while not name.isalpha():
    print('Entered Name is invalid')
    name = input('Please Enter Your Name Sir:     ')
 if name.isalpha()  or name.isspace():
    print('Hello Mr.' + name)
    select_mmenu('main-menu.txt')

if all(lett.isalpha() or lett.isspace() for lett in name):

import re  # at the top of your module

if re.match(r"[sw]+", name):