def execute(self):
        """ Adds a todo item to the list. """
        if not super().execute():
            return False

        self.printer.add_filter(PrettyPrinterNumbers(self.todolist))
        self._process_flags()

        if self.from_file:
            try:
                new_todos = self.get_todos_from_file()

                for todo in new_todos:
                    self._add_todo(todo)
            except (IOError, OSError):
                self.error('File not found: ' + self.from_file)
        else:
            if self.text:
                self._add_todo(self.text)
            else:
                self.error(self.usage())