docs: 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