code: def calibration_lines(freqs, data, tref=None):
      
      if tref is None:
          tref = float(data.start_time)
      for freq in freqs:
          measured_line = matching_line(freq, data, tref,
                                        bin_size=data.duration)
          data -= measured_line.data.real
  
      return data
docs: Extract the calibration lines from strain data.
  
      Parameters
      ----------
      freqs: list
          List containing the frequencies of the calibration lines.
      data: pycbc.types.TimeSeries
          Strain data to extract the calibration lines from.
      tref: {None, float}, optional
          Reference time for the line. If None, will use data.start_time.
  
      Returns
      -------
      data: pycbc.types.TimeSeries
          The strain data with the calibration lines removed.