keras-team/keras · error · ValueError

`attention_axes` must be an int, list, or tuple.Received: at

Error message

`attention_axes` must be an int, list, or tuple.Received: attention_axes={attention_axes}

What it means

Error "`attention_axes` must be an int, list, or tuple.Received: attention_axes={attention_axes}" thrown in keras-team/keras.

Source

Thrown at keras/src/layers/attention/multi_head_attention.py:186

            except:
                raise ValueError(
                    f"Invalid `output_shape`: {output_shape}. When "
                    "specified, the `output_shape` should be of type tuple, "
                    "list, or int."
                )
        self._output_shape = output_shape
        self._flash_attention = flash_attention or is_flash_attention_enabled()
        self._kernel_initializer = initializers.get(kernel_initializer)
        self._bias_initializer = initializers.get(bias_initializer)
        self._kernel_regularizer = regularizers.get(kernel_regularizer)
        self._bias_regularizer = regularizers.get(bias_regularizer)
        self._activity_regularizer = regularizers.get(activity_regularizer)
        self._kernel_constraint = constraints.get(kernel_constraint)
        self._bias_constraint = constraints.get(bias_constraint)
        if isinstance(attention_axes, int):
            attention_axes = (attention_axes,)
        elif attention_axes and not isinstance(attention_axes, (list, tuple)):
            raise ValueError(
                "`attention_axes` must be an int, list, or tuple."
                f"Received: attention_axes={attention_axes}"
            )
        self._attention_axes = attention_axes
        if sliding_window is not None and (
            not isinstance(sliding_window, int) or sliding_window <= 0
        ):
            raise ValueError(
                "`sliding_window` must be `None` or a positive integer. "
                f"Received: sliding_window={sliding_window}"
            )
        self._sliding_window = sliding_window
        self.seed = seed

        self._inverse_sqrt_key_dim = 1.0 / math.sqrt(float(self._key_dim))

        # Check for flash attention constraints
        if self._flash_attention and self._dropout > 0.0:

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/layers/attention/multi_head_attention.py:186 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/e4e9b9b6d7bbcf07. Report an issue: GitHub.