code: def get_waveform_filter(out, template=None, **kwargs):
      
      n = len(out)
  
      input_params = props(template, **kwargs)
  
      if input_params['approximant'] in filter_approximants(_scheme.mgr.state):
          wav_gen = filter_wav[type(_scheme.mgr.state)]
          htilde = wav_gen[input_params['approximant']](out=out, **input_params)
          htilde.resize(n)
          htilde.chirp_length = get_waveform_filter_length_in_time(**input_params)
          htilde.length_in_time = htilde.chirp_length
          return htilde
  
      if input_params['approximant'] in fd_approximants(_scheme.mgr.state):
          wav_gen = fd_wav[type(_scheme.mgr.state)]
  
          duration = get_waveform_filter_length_in_time(**input_params)
          hp, _ = wav_gen[input_params['approximant']](duration=duration,
                                                 return_hc=False, **input_params)
  
          hp.resize(n)
          out[0:len(hp)] = hp[:]
          hp = FrequencySeries(out, delta_f=hp.delta_f, copy=False)
  
          hp.length_in_time = hp.chirp_length = duration
          return hp
  
      elif input_params['approximant'] in td_approximants(_scheme.mgr.state):
          wav_gen = td_wav[type(_scheme.mgr.state)]
          hp, _ = wav_gen[input_params['approximant']](**input_params)
          # taper the time series hp if required
          if 'taper' in input_params.keys() and \
                  input_params['taper'] is not None:
              hp = wfutils.taper_timeseries(hp, input_params['taper'],
                                            return_lal=False)
          return td_waveform_to_fd_waveform(hp, out=out)
  
      else:
          raise ValueError("Approximant %s not available" %
                              (input_params['approximant']))
docs: Return a frequency domain waveform filter for the specified approximant