code: func flagVolumeCapabilities(fs *flag.FlagSet, addr *volumeCapabilitySliceArg) {
  	fs.Var(
  		addr,
  		"cap",
  		`One or more volume capabilities may be specified using the following
          format:
  `+flagVolumeCapabilityDescSuffix)
  }
docs: // flagVolumeCapabilities adds the --cap flag to the specified flagset.