docs: def dbfpack(fn, usecols=None):
      """Return a ChannelPack instance loaded with dbf data file fn.
  
      This is a lazy function to get a loaded instance, using pulldbf
      module."""
  
      loadfunc = pulldbf.dbf_asdict
      cp = ChannelPack(loadfunc)
      cp.load(fn, usecols)
      names = pulldbf.channel_names(fn, usecols)
      cp.set_channel_names(names)
      # cp.set_basefilemtime()
      return cp