def _on_add_library(self, *event):
        """Callback method handling the addition of a new library
        """
        self.view['library_tree_view'].grab_focus()
        if react_to_event(self.view, self.view['library_tree_view'], event):
            temp_library_name = "<LIB_NAME_%s>" % self._lib_counter
            self._lib_counter += 1
            library_config = self.core_config_model.get_current_config_value("LIBRARY_PATHS", use_preliminary=True,
                                                                             default={})
            library_config[temp_library_name] = "<LIB_PATH>"
            self.core_config_model.set_preliminary_config_value("LIBRARY_PATHS", library_config)
            self._select_row_by_column_value(self.view['library_tree_view'], self.library_list_store,
                                             self.KEY_STORAGE_ID, temp_library_name)
            return True
Callback method handling the addition of a new library