code: def profile_tilt(data, mask):
      
      params = lmfit.Parameters()
      params.add(name="mx", value=0)
      params.add(name="my", value=0)
      params.add(name="off", value=np.average(data[mask]))
      fr = lmfit.minimize(tilt_residual, params, args=(data, mask))
      bg = tilt_model(fr.params, data.shape)
      return bg
docs: Fit a 2D tilt to `data[mask]`