File approve event handler

def OnApprove(self, event):
        """File approve event handler"""

        if not self.main_window.safe_mode:
            return

        msg = _(u"You are going to approve and trust a file that\n"
                u"you have not created yourself.\n"
                u"After proceeding, the file is executed.\n \n"
                u"It may harm your system as any program can.\n"
                u"Please check all cells thoroughly before\nproceeding.\n \n"
                u"Proceed and sign this file as trusted?")

        short_msg = _("Security warning")

        if self.main_window.interfaces.get_warning_choice(msg, short_msg):
            # Leave safe mode
            self.main_window.grid.actions.leave_safe_mode()

            # Display safe mode end in status bar

            statustext = _("Safe mode deactivated.")
            post_command_event(self.main_window, self.main_window.StatusBarMsg,
                               text=statustext)