validate.py

import string

def validate(fqdn):
	"""docstring for validate"""
	valid_chars = list(string.ascii_letters + string.digits + '-' + '.')

	if all(char in valid_chars for char in fqdn):
	    return True
	else:
            return False


if validate('this is not a valid fqdn'):
	print('not working as it should')

if validate('127.0.0.1'):
	print ('maybe working as it should')