How to add absorption to the model and set upper and lower limits

[unknowner-m]

I am a graduate student and I am trying to fit the NIRSPEC g395h spectrum using PAHFIT. According to Lai+2020, I added the short wavelength feature in the yaml file.

PAH_3.3:
  kind: dust_feature
  wavelength: 3.29
  fwhm: 0.0418

PAH_3.4:
  kind: dust_feature
  wavelength: 3.4
  fwhm: 0.0299

PAH_3.47:
  kind: dust_feature
  wavelength: 3.47
  fwhm: 0.1
##########################
# Absorption Model      #
##########################
H2O_absorption:
  kind: absorption
  tau: 2.5
  wavelength: 3.05
  fwhm: 0.406

CO2_absorption:
  kind: absorption
  tau: 1.532
  wavelength: 4.27
  fwhm: 0.033

CO_absorption:
  kind: absorption
  tau: 0.4
  wavelength: 4.67
  fwhm: 0.1

When I start running the script

model = Model.from_yaml('model.yaml')
model.guess(spec)
model.fit(spec, maxiter=10000)
display(model)
model.plot(spec)

I got the following error

---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
Cell In[67], [line 12](vscode-notebook-cell:?execution_count=67&line=12)
     [10](vscode-notebook-cell:?execution_count=67&line=10) model.fit(spec, maxiter=10000)
     [11](vscode-notebook-cell:?execution_count=67&line=11) display(model)
---> [12](vscode-notebook-cell:?execution_count=67&line=12) model.plot(spec)

File d:\Anaconda\envs\pahfit\Lib\site-packages\pahfit\model.py:538, in Model.plot(self, spec, redshift, use_instrument_fwhm, label_lines, scalefac_resid, **errorbar_kwargs)
    [535] ext_model = S07_attenuation(tau_sil=tau)(lam_mod)
    [537](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:537) if has_abs:
--> [538](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:538)     raise NotImplementedError(
    [539](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:539)         "plotting absorption features not implemented yet"
    [540](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:540)     )
    [542](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:542) if has_att or has_abs:
    [543](file:///D:/Anaconda/envs/pahfit/Lib/site-packages/pahfit/model.py:543)     ax_att = ax.twinx()  # axis for plotting the extinction curve

NotImplementedError: plotting absorption features not implemented yet

Does this mean that the absorption feature cannot be applied in the current version?

In addition, I checked the feature table and found that the wavelength and fwhm of the features I added did not have upper and lower limits set. How should I set them correctly?