def assert_valid_key_size(key)
      expected_key_size = model_key.size
      actual_key_size   = key.size

      if actual_key_size != expected_key_size
        raise ArgumentError, "The number of arguments for the key is invalid, expected #{expected_key_size} but was #{actual_key_size}"
      end
    end
def assert_valid_key_size(key)
      expected_key_size = model_key.size
      actual_key_size   = key.size

      if actual_key_size != expected_key_size
        raise ArgumentError, "The number of arguments for the key is invalid, expected #{expected_key_size} but was #{actual_key_size}"
      end
    end
Raises an exception if #get receives the wrong number of arguments

 @param [Array] key
   the key value

 @return [undefined]

 @raise [UpdateConflictError]
   raise if the resource is dirty

 @api private