code: def add_gate_option_group(parser):
      
      gate_group = parser.add_argument_group("Options for gating data.")
  
      gate_group.add_argument("--gate", nargs="+", type=str,
                              metavar="IFO:CENTRALTIME:HALFDUR:TAPERDUR",
                              help="Apply one or more gates to the data before "
                                   "filtering.")
      gate_group.add_argument("--gate-overwhitened", action="store_true",
                              help="Overwhiten data first, then apply the "
                                   "gates specified in --gate. Overwhitening "
                                   "allows for sharper tapers to be used, "
                                   "since lines are not blurred.")
      gate_group.add_argument("--psd-gate", nargs="+", type=str,
                              metavar="IFO:CENTRALTIME:HALFDUR:TAPERDUR",
                              help="Apply one or more gates to the data used "
                                   "for computing the PSD. Gates are applied "
                                   "prior to FFT-ing the data for PSD "
                                   "estimation.")
      return gate_group
docs: Adds the options needed to apply gates to data.
  
      Parameters
      ----------
      parser : object
          ArgumentParser instance.