docs: def delete(cls, bucket, key):
          """Delete an object.
  
          Technically works by creating a new version which works as a delete
          marker.
  
          :param bucket: The bucket (instance or id) to delete the object from.
          :param key: Key of object.
          :returns: Created delete marker object if key exists else ``None``.
          """
          bucket_id = as_bucket_id(bucket)
  
          obj = cls.get(bucket_id, key)
          if obj:
              return cls.create(as_bucket(bucket), key)
          return None