Gives vowel count of string entered. Accepted string-> without number i.e alphabets A-Z a-z and all symbo

vowel_count.py

# Calling
print 'allowed input - any string without number(s) i.e. (^[[\S|\s][\d+][\S|\s]])'
string_input = raw_input('Enter String: ')

# using regex to validate the input
import re
if re.search(r'\d+', string_input):
    exit('error - string must not consist any number')

# list of accepted vowels
vowels = ['a','e','i','o','u','y']
char_list = list(string_input)
count = 0
for char in char_list:
    if char.lower() in vowels:
        count += 1
print count