def _stack(values, axis=0, name='stack'):
    del name
    if (axis is None):
        raise ValueError('None values for `axis` argument not supported.')
    values = _args_to_matching_arrays(values)
    return np.stack(values, axis=axis)
def _stack(values, axis=0, name='stack'):
    del name
    if (axis is None):
        raise ValueError('None values for `axis` argument not supported.')
    values = _args_to_matching_arrays(values)
    return np.stack(values, axis=axis)