def METHOD_NAME(Obs_xml, Obs_data, axes1):
    #=== SPECIAL CODE === Theis EXAMPLE === Water Table is 12.0 m 
    r_vals = []
    for obs in Obs_data.observations.values():
        r_vals.append(obs.coordinate[0])
    r_vals = set(r_vals)
    r_vals = list(r_vals)
    r_vals.sort()
    colors = ['g','r','b']
    cmap = dict((rval,color) for (rval,color) in zip(r_vals, colors))
    for obs in Obs_data.observations.values():
        color = cmap[obs.coordinate[0]]
        pres0 = 101325 -9806.65 * (obs.coordinate[2] - 20)
        pres_drop = (pres0 - numpy.array([obs.data]))
        drawdown = pres_drop / 9806.65
        axes1.scatter(obs.times, drawdown, marker='s', s=25, c=color)
    return cmap