Implement a Python function to tally the number of vowels in a string.
Write a function that counts both lower-case and upper-case vowels in a given string `s` in English. In English, we define a vowel as any of these five letters: 'a', 'e', 'i', 'o', 'u'. ### Parameters - `s` (str): A non-empty string with a maximum length of `10^5`. The string may contain English letters, spaces, punctuation marks, and digits. ### Return Value - Returns an integer, which is the count of vowels present in the string `s`. ### Examples ```python # In "I love you", there are 5 vowels 'I', 'o', 'e', 'o', 'u' count_vowels("I love you") # 5 # In "Hello World", there are 3 vowels: 'e', 'o', 'o' count_vowels("Hello World") # 3 # In "Programming", there are 3 vowels: 'o', 'a', 'i' count_vowels("Programming") # 3 ```