An error is triggered when calling a method which does not exist.
Place the editor cursor on the error's line and press Ctrl + 1, select Declare function ... or Declare task ... from the list of quick fix proposals and press Enter.
The method stub declaration is inserted in the appropriate scope.
Note: The method signature (return type, argument names and types) is automatically detected from context.
Tip: You may change the function's return type, as well as the name and type of each argument. Press Tab key to switch between the edit boxes, and Enter when done.