def search4vowels(phrase: str) -> set:
    """Display any vowels found in supplied phrase."""
    vowels = set('aeiou')
    return vowels.intersection(set(phrase))


def search4letters(phrase: str, letters: str = 'aeiou') -> set:
    """Returns a set of the 'letters' found in 'phrase'."""
    return set(letters).intersection(set(phrase))


if __name__ == '__main__':
    print(*sorted(search4letters('some string that i need to pass here')))
    print(*sorted(search4letters('galaxy', 'xyz')))
