Fatal IndexError when `analog_anti_aliasing_file` assignment is empy in parameter model (.ini) file

model.analog_aa_or_ai_filter_response fails with an IndexError if the analog_anti_aliasing_file line in the pydarm parameter set is blank after the "=" symbol (see L45). Commenting the line resolves this (i.e. does not raise the error & executes to completion).

I'm not sure if this is the intended behavior. I seem to recall @evan-goetz saying it should be fine to leave the assignment blank so I'm reporting this here in case this flags a bug.

louis.dartez@opslogin0: conda activate pydarm-cds-dev
(pydarm-cds-dev) louis.dartez@opslogin0: python -m pydarm report --no-display
loading config: /ligo/groups/cal/ifo/H1/pydarm_cmd_H1.yaml
finding last measurement set...
mset_list: ['20221209T2206Z', '20230127T2140Z']
measurement set: /ligo/groups/cal/data/H1/measurements/20230127T2140Z
measurement set: 20230127T2140Z
Really regenerate report for measurement set 20230127T2140Z [Y|n]? y
generating report for 20230127T2140Z...
loading measurement: Sensing...
loading measurement: Actuation/L1...
loading measurement: Actuation/L2...
loading measurement: Actuation/L3...
generating sensing report...
Traceback (most recent call last):
  File "/ligo/home/louis.dartez/.conda/envs/pydarm-cds-dev/lib/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/ligo/home/louis.dartez/.conda/envs/pydarm-cds-dev/lib/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/__main__.py", line 90, in <module>
    main()
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/__main__.py", line 84, in main
    func(args)
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/cmd/report.py", line 740, in main
    report.add_figure(sensing(mset))
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/cmd/report.py", line 488, in sensing
    processed_sensing.get_processed_measurement_response()
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/measurement.py", line 821, in get_processed_measurement_response
    self.sensing.sensing_residual(frequencies)
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/sensing.py", line 567, in sensing_residual
    self.omc_combine_path_responses(frequencies))
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/sensing.py", line 492, in omc_combine_path_responses
    response += self.omc_path_response(self.omc_path_names[n],
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/sensing.py", line 434, in omc_path_response
    analog_readout_response = self.omc_analog_dcpd_readout_response(
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/sensing.py", line 322, in omc_analog_dcpd_readout_response
    self.analog_aa_or_ai_filter_response(frequencies, idx)
  File "/ligo/home/louis.dartez/repos/pydarm/pydarm/model.py", line 306, in analog_aa_or_ai_filter_response
    path = self.analog_anti_aliasing_file[idx]
IndexError: list index out of range
(pydarm-cds-dev) louis.dartez@opslogin0: