ShortcutAction 
  Tries to parse the given string into an action.
On success, the parsed action is returned. When parsing failed, null is returned.
The accepted strings are:
- nothing, for- GtkNothingAction
- activate, for- GtkActivateAction
- mnemonic-activate, for- GtkMnemonicAction
- action(NAME), for a- GtkNamedActionfor the action named- NAME
- signal(NAME), for a- GtkSignalActionfor the signal- NAME
Return
a new GtkShortcutAction
Parameters
string
the string to parse
constructor(gtkShortcutActionPointer: <Error class: unknown class><<Error class: unknown class>>)(source)