def epd_kepler_lightcurve(lcdict,
                          xccol='mom_centr1',
                          yccol='mom_centr2',
                          timestoignore=None,
                          filterflags=True,
                          writetodict=True,
                          epdsmooth=5):
    '''This runs EPD on the Kepler light curve.

    Following Huang et al. 2015, we fit the following EPD function to a smoothed
    light curve, and then subtract it to obtain EPD corrected magnitudes::

        f = c0 +
            c1*sin(2*pi*x) + c2*cos(2*pi*x) + c3*sin(2*pi*y) + c4*cos(2*pi*y) +
            c5*sin(4*pi*x) + c6*cos(4*pi*x) + c7*sin(4*pi*y) + c8*cos(4*pi*y) +
            c9*bgv + c10*bge

    By default, this function removes points in the Kepler LC that have ANY
    quality flags set.

    Parameters
    ----------

    lcdict : lcdict
        An `lcdict` produced by `consolidate_kepler_fitslc` or
        `read_kepler_fitslc`.

    xcol,ycol : str
        Indicates the x and y coordinate column names to use from the Kepler LC
        in the EPD fit.

    timestoignore : list of tuples
        This is of the form::

            [(time1_start, time1_end), (time2_start, time2_end), ...]

        and indicates the start and end times to mask out of the final
        lcdict. Use this to remove anything that wasn't caught by the quality
        flags.

    filterflags : bool
        If True, will remove any measurements that have non-zero quality flags
        present. This usually indicates an issue with the instrument or
        spacecraft.

    writetodict : bool
        If writetodict is True, adds the following columns to the lcdict::

            epd_time = time array
            epd_sapflux = uncorrected flux before EPD
            epd_epdsapflux = corrected flux after EPD
            epd_epdsapcorr = EPD flux corrections
            epd_bkg = background array
            epd_bkg_err = background errors array
            epd_xcc = xcoord array
            epd_ycc = ycoord array
            epd_quality = quality flag array

        and updates the 'columns' list in the lcdict as well.

    epdsmooth : int
        Sets the number of light curve points to smooth over when generating the
        EPD fit function.

    Returns
    -------

    tuple
        Returns a tuple of the form: (times, epdfluxes, fitcoeffs, epdfit)

    '''

    times, fluxes, background, background_err = (lcdict['time'],
                                                 lcdict['sap']['sap_flux'],
                                                 lcdict['sap']['sap_bkg'],
                                                 lcdict['sap']['sap_bkg_err'])
    xcc = lcdict[xccol]
    ycc = lcdict[yccol]
    flags = lcdict['sap_quality']

    # filter all bad LC points as noted by quality flags
    if filterflags:

        nbefore = times.size

        filterind = flags == 0

        times = times[filterind]
        fluxes = fluxes[filterind]
        background = background[filterind]
        background_err = background_err[filterind]
        xcc = xcc[filterind]
        ycc = ycc[filterind]
        flags = flags[filterind]

        nafter = times.size
        LOGINFO('applied quality flag filter, ndet before = %s, ndet after = %s'
                % (nbefore, nafter))


    # remove nans
    find = (npisfinite(xcc) & npisfinite(ycc) &
            npisfinite(times) & npisfinite(fluxes) &
            npisfinite(background) & npisfinite(background_err))

    nbefore = times.size

    times = times[find]
    fluxes = fluxes[find]
    background = background[find]
    background_err = background_err[find]
    xcc = xcc[find]
    ycc = ycc[find]
    flags = flags[find]

    nafter = times.size
    LOGINFO('removed nans, ndet before = %s, ndet after = %s'
            % (nbefore, nafter))


    # exclude all times in timestoignore
    if (timestoignore and
        isinstance(timestoignore, list) and
        len(timestoignore) > 0):

        exclind = npfull_like(times,True)
        nbefore = times.size

        # apply all the masks
        for ignoretime in timestoignore:
            time0, time1 = ignoretime[0], ignoretime[1]
            thismask = (times > time0) & (times < time1)
            exclind = exclind & thismask

        # quantities after masks have been applied
        times = times[exclind]
        fluxes = fluxes[exclind]
        background = background[exclind]
        background_err = background_err[exclind]
        xcc = xcc[exclind]
        ycc = ycc[exclind]
        flags = flags[exclind]

        nafter = times.size
        LOGINFO('removed timestoignore, ndet before = %s, ndet after = %s'
                % (nbefore, nafter))


    # now that we're all done, we can do EPD
    # first, smooth the light curve
    smoothedfluxes = median_filter(fluxes, size=epdsmooth)

    # initial fit coeffs
    initcoeffs = npones(11)

    # fit the the smoothed mags and find better coeffs
    leastsqfit = leastsq(_epd_residual,
                         initcoeffs,
                         args=(smoothedfluxes,
                               xcc, ycc,
                               background, background_err))

    # if the fit succeeds, then get the EPD fluxes
    if leastsqfit[-1] in (1,2,3,4):

        fitcoeffs = leastsqfit[0]
        epdfit = _epd_function(fitcoeffs,
                               fluxes,
                               xcc,
                               ycc,
                               background,
                               background_err)
        epdfluxes = npmedian(fluxes) + fluxes - epdfit

        # write these to the dictionary if requested
        if writetodict:

            lcdict['epd'] = {}

            lcdict['epd']['time'] = times
            lcdict['epd']['sapflux'] = fluxes
            lcdict['epd']['epdsapflux'] = epdfluxes
            lcdict['epd']['epdsapcorr'] = epdfit
            lcdict['epd']['bkg'] = background
            lcdict['epd']['bkg_err'] = background_err
            lcdict['epd']['xcc'] = xcc
            lcdict['epd']['ycc'] = ycc
            lcdict['epd']['quality'] = flags

            for newcol in ['epd.time','epd.sapflux',
                           'epd.epdsapflux','epd.epdsapcorr',
                           'epd.bkg','epd.bkg.err',
                           'epd.xcc','epd.ycc',
                           'epd.quality']:

                if newcol not in lcdict['columns']:
                    lcdict['columns'].append(newcol)

        return times, epdfluxes, fitcoeffs, epdfit

    else:

        LOGERROR('could not fit EPD function to light curve')
        return None, None, None, None
This runs EPD on the Kepler light curve.

    Following Huang et al. 2015, we fit the following EPD function to a smoothed
    light curve, and then subtract it to obtain EPD corrected magnitudes::

        f = c0 +
            c1*sin(2*pi*x) + c2*cos(2*pi*x) + c3*sin(2*pi*y) + c4*cos(2*pi*y) +
            c5*sin(4*pi*x) + c6*cos(4*pi*x) + c7*sin(4*pi*y) + c8*cos(4*pi*y) +
            c9*bgv + c10*bge

    By default, this function removes points in the Kepler LC that have ANY
    quality flags set.

    Parameters
    ----------

    lcdict : lcdict
        An `lcdict` produced by `consolidate_kepler_fitslc` or
        `read_kepler_fitslc`.

    xcol,ycol : str
        Indicates the x and y coordinate column names to use from the Kepler LC
        in the EPD fit.

    timestoignore : list of tuples
        This is of the form::

            [(time1_start, time1_end), (time2_start, time2_end), ...]

        and indicates the start and end times to mask out of the final
        lcdict. Use this to remove anything that wasn't caught by the quality
        flags.

    filterflags : bool
        If True, will remove any measurements that have non-zero quality flags
        present. This usually indicates an issue with the instrument or
        spacecraft.

    writetodict : bool
        If writetodict is True, adds the following columns to the lcdict::

            epd_time = time array
            epd_sapflux = uncorrected flux before EPD
            epd_epdsapflux = corrected flux after EPD
            epd_epdsapcorr = EPD flux corrections
            epd_bkg = background array
            epd_bkg_err = background errors array
            epd_xcc = xcoord array
            epd_ycc = ycoord array
            epd_quality = quality flag array

        and updates the 'columns' list in the lcdict as well.

    epdsmooth : int
        Sets the number of light curve points to smooth over when generating the
        EPD fit function.

    Returns
    -------

    tuple
        Returns a tuple of the form: (times, epdfluxes, fitcoeffs, epdfit)