count_vowels.py

defcount_vowels(s: str) ->int:
"""
 Count the number of vowels in a given string.

 :param s: Input string to count vowels in.
 :return: Number of vowels in the input string.

 Examples:
 >>> count_vowels("hello world")
 3
 >>> count_vowels("HELLO WORLD")
 3
 >>> count_vowels("123 hello world")
 3
 >>> count_vowels("")
 0
 >>> count_vowels("a quick brown fox")
 5
 >>> count_vowels("the quick BROWN fox")
 5
 >>> count_vowels("PYTHON")
 1
 """
ifnotisinstance(s, str):
raiseValueError("Input must be a string")

vowels="aeiouAEIOU"
returnsum(1forcharinsifcharinvowels)


if__name__=="__main__":
fromdoctestimporttestmod

testmod()