Unable to convolve GAIA DR2 bandpasses with ck04 models

I am attempting to create ck04 stellar model fluxes with the GAIA passbands. I downloaded the Revised GAIA bandpasses from https://www.cosmos.esa.int/web/gaia/iow_20180316. Using the online guide, I did the following:

`wlg,g,gbp,grp=np.loadtxt('GaiaDR2_RevisedPassbands.dat',unpack=True,usecols=(0,1,3,5))
f=Filter()
f.name="GAIA_G"
f.central_wavelength=0.6419*u.micron
f.nu=(2.99792458e8/(wlg*1e-9))*u.Hz
f.response=g

convolve_model_dir(model_dir, [f])`

I have given the model_dir where the ck04 models reside along with the models.conf file. The result in the fits file that is written shows 0 flux for every wavelength. I noticed that in filter.py class, the condition on line 129 is never met:

`if nu2 != nu1:`

Hope you can help me solve this issue.

Thanks!

Start with filter.py around line 129 and trace how the Filter created from GaiaDR2_RevisedPassbands.dat is passed to convolve_model_dir. Reproduce the zero-flux result using the ck04 model directory and models.conf, then verify that the generated FITS output contains the expected convolved flux rather than zeros.

Written by the indexing model from the issue text.