Description:
When coding errors are present in a closelistener class for some bad coding the expected behaviour is not invoked, while no errors are thrown
I have python opened is a separate editor, CTRL +S, then run the code in libO
(no IDE)

Steps to Reproduce:
def dialog2(oEvent):


    oForm = XSCRIPTCONTEXT.getDocument()

    time.sleep(0.5)
    AB = CloseListener()
    oForm.addCloseListener(AB)

class CloseListener(unohelper.Base, XCloseListener):

    def notifyClosing(self, evt: FrameActionEvent):
       # msgbox("notifyClosing")
       pass

    def queryClosing(self,evt: FrameActionEvent):#,   ownership=True):
        msgbox("qC"+str(9))
        return
    def disposing(self, evt: EventObject):
        pass

0) dialog2 is attached to the 'when loading' form event
1) above code throws no exception, msgbox is not shown, form closes normally

2) if ):# is removed, closing of the form shows the msgbox

3) removing the str function in the msgbox,

4) def queryClosing(self,evt: FrameActionEvent, ownership=True)
without the : an error is thrown

Actual Results:
re 1) no error shown, form closes normally
re 2) good coding, as expected
re 3) no error shown, form closes normally
re 4) bad coding, error is thrown, the only correct case in this list

Expected Results:
re 1) expected is an error like 'expected 2 parameters, got 1
re 2) behaviour is as expected
re 3) should raise the error 'cannot concatenate string and integers'
re 4) behaviour as expected


Reproducible: Always


User Profile Reset: No


OpenGL enabled: Yes

Additional Info:
Version: 6.4.7.2
Build ID: 1:6.4.7-0ubuntu0.20.04.1
CPU threads: 4; OS: Linux 5.4; UI render: default; VCL: gtk3;