code: def get_bucket(seq_len: int, buckets: List[int]) -> Optional[int]:
      
      bucket_idx = bisect.bisect_left(buckets, seq_len)
      if bucket_idx == len(buckets):
          return None
      return buckets[bucket_idx]
docs: Given sequence length and a list of buckets, return corresponding bucket.
  
      :param seq_len: Sequence length.
      :param buckets: List of buckets.
      :return: Chosen bucket.