code: def _get_wanted_channels(wanted_sig_names, record_sig_names, pad=False):
      
      if pad:
          return [record_sig_names.index(s) if s in record_sig_names else None for s in wanted_sig_names]
      else:
          return [record_sig_names.index(s) for s in wanted_sig_names if s in record_sig_names]
docs: Given some wanted signal names, and the signal names contained in a
      record, return the indices of the record channels that intersect.
  
      Parameters
      ----------
      wanted_sig_names : list
          List of desired signal name strings
      record_sig_names : list
          List of signal names for a single record
      pad : bool, optional
          Whether the output channels is to always have the same number
          of elements and the wanted channels. If True, pads missing
          signals with None.
  
      Returns
      -------
      wanted_channel_inds