def page_changing ( event ):
    # Get the page the user is trying to go to:
    page = event.GetPage()
    if event.GetDirection():
       new_page = page.GetNext()
    else:
       new_page = page.GetPrev()

    # If the page has a disabled PageGroupEditor object, veto the page change:
    if ((new_page is not None) and
        (new_page.editor is not None) and
        (not new_page.editor.enabled)):
        event.Veto()

        # If their is a message associated with the editor, display it:
        msg = new_page.editor.msg
        if msg != '':
            wx.MessageBox( msg )

#-------------------------------------------------------------------------------
#  'UIWizardPage' class:
#-------------------------------------------------------------------------------
Invoke list_get() with negative index
dataset/ETHPy150Open enthought/traitsui/traitsui/wx/ui_wizard.py/page_changing--crossover with--dataset/ETHPy150Open aerospike/aerospike-client-python/test/old_tests/_test_list_get.py/TestListGet.test_list_get_with_negative_index