code: func ValidateProcMountType(fldPath *field.Path, procMountType core.ProcMountType) *field.Error {
  	switch procMountType {
  	case core.DefaultProcMount, core.UnmaskedProcMount:
  		return nil
  	default:
  		return field.NotSupported(fldPath, procMountType, []string{string(core.DefaultProcMount), string(core.UnmaskedProcMount)})
  	}
  }
docs: // ValidateProcMountType tests that the argument is a valid ProcMountType.