def phaseplot_values(species):
    """
    A convenience function to get a dictionary of values, to allow generalization of the PhasePlot class.

    The keys you can pull for phase plots are `x`, `v_x`, `v_y` and `v_z`.

    Parameters
    ----------
    species : Species
        A species to draw data from

    Returns
    -------
    A dictionary of phase plot values.
    """
    return {"x":                           species.position_history,
            "v_x": species.velocity_history[:, :, 0],
            "v_y": species.velocity_history[:, :, 1],
            "v_z": species.velocity_history[:, :, 2],
            }