How to use the spacepy.coordinates function in spacepy

def runPA(quality):
    #test for range of pitch angles
    ticks = spt.tickrange('2002-04-18', '2002-04-19', 1)
    loci = spc.Coords([[-4,0,0], [-5,0,0]], 'SM', 'car')
    vals = []
    for pp in range(1,91):
        dum = lgmpy.get_Lstar(loci.data[1], ticks.UTC[1], alpha=pp, coord_system='SM', 
                              Bfield='Lgm_B_cdip', extended_out=True, LstarQuality=quality)
        try:
            vals.extend(dum[pp]['Lstar'])
        except (IndexError, TypeError): #get_Lstar returns a 0-D nan in some cases...
            vals.extend([dum[pp]['Lstar'].tolist()])
    fig = plt.figure()
    expect = float(tb.hypot(loci.data[1]))
    plt.plot(100*(dm.dmarray(vals)-expect)/expect, drawstyle='steps-mid')
    plt.ylim([-0.01, 0.01])
    plt.xlabel('Pitch Angle')
    plt.ylabel('100*(L* - L*$_{exp}$)/L*$_{exp}$')
    plt.title('Cent. dipole [-5,0,0]$_{SM}$'+'; Quality ({0})'.format(str(quality)))
    figname = 'MagEphem_CDIP_test_q{0}'.format(str(quality))   #'LGM_L*_vs_PA_cdip_q{0}'.format(str(quality))

def runPAdungey(quality):
    #test for range of pitch angles
    ticks = spt.tickrange('2002-04-18', '2002-04-19', 1)
    loci = spc.Coords([[-4,0,0], [-5,0,0]], 'SM', 'car')
    vals = []
    for pp in range(1,91):
        dum = lgmpy.get_Lstar(loci.data[1], ticks.UTC[1], alpha=pp, coord_system='SM', 
                              Bfield='Lgm_B_Dungey', extended_out=True, LstarQuality=quality)
        try:
            vals.extend(dum[pp]['Lstar'])
        except (IndexError, TypeError): #get_Lstar returns a 0-D nan in some cases...
            vals.extend([dum[pp]['Lstar'].tolist()])
    fig = plt.figure()
    expect = dungeyLeq(tb.hypot(loci.data[1]))
    #print(expect)
    plt.plot(100*(dm.dmarray(vals)-expect)/expect, drawstyle='steps-mid')
    plt.ylim([-0.01, 0.01])
    plt.xlabel('Pitch Angle')
    plt.ylabel('100*(L* - L*$_{exp}$)/L*$_{exp}$')
    plt.title('Dungey model [-5,0,0]$_{SM}$'+'; Quality ({0})'.format(str(quality)))