input: Write a function to find the most repeated character in a given string using Counter from collections.
  assert most_repeated_character("hello") == 'l'
  assert most_repeated_character("aabbcc") == 'a'
  assert most_repeated_character("abcabcabc") == 'a'
output: def most_repeated_character(s: str) -> str:
      from collections import Counter
      counter = Counter(s)
      most_common = counter.most_common(1)
      return most_common[0][0] if most_common else ''