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# count_vowels
# Returns number of vowels in provided string.

# Use a regular expression to count the number of vowels (A, E, I, O, U) in a string.

import re


def count_vowels(string):
    return len(len(re.findall(r'[aeiou]', string, re.IGNORECASE)))


count_vowels('foobar')  # 3
count_vowels('gym')  # 0
