code: def _check_header(channel_file, s_freq):
      
      hdr = _read_header(channel_file)
  
      assert int(hdr['header_bytes']) == HDR_LENGTH
      assert int(hdr['blockLength']) == BLK_LENGTH
      assert int(hdr['sampleRate']) == s_freq
  
      return float(hdr['bitVolts'])
docs: For each file, make sure that the header is consistent with the
      information in the text file.
  
      Parameters
      ----------
      channel_file : Path
          path to single filename with the header
      s_freq : int
          sampling frequency
  
      Returns
      -------
      int
          gain from digital to microvolts (the same information is stored in
          the Continuous_Data.openephys but I trust the header for each file more.