def _box(responses, box_min, box_max):
    """Projects responses from box [box_min, box_max] to [0, 1].

    Arguments
    ---------
    responses : numpy array
       An array of values in [box_min, box_max] to be projected.
    box_min : float
       The minimum value of a box containing responses.
    box_max : float
       The maximum value of a box containing responses.

    Returns
    -------
    numpy array
       responses projected onto [0, 1].
    """
    return (responses - box_min) / (box_max - box_min)
