def get_closest_vowel(word):
    if len(word) < 3:
        return ""
    vowels = {"a", "e", "i", "o", "u", "A", "E", 'O', 'U', 'I'}
    for i in range(len(word)-2, 0, -1):
        if word[i] in vowels:
            if (word[i+1] not in vowels) and (word[i-1] not in vowels):
                return word[i]
    return ""
from typing import List
def separate_paren_groups(paren_string: str) -> List[str]:
    result = []
    current_string = []
    current_depth = 0
    for c in paren_string:
        if c == '(':
            current_depth += 1
            current_string.append(c)
        elif c == ')':
            current_depth -= 1
            current_string.append(c)
            if current_depth == 0:
                result.append(''.join(current_string))
                current_string.clear()
    return result