im still new in ROS2 i dont have basic knowledge about it, when i run my launch file it prompt this error

[INFO] [launch]: All log files can be found below /home/dianne/.ros/log/2023-07-08-13-06-38-095053-dianne-3519
[INFO] [launch]: Default logging verbosity is set to INFO
[ERROR] [launch]: Caught exception in launch (see debug for traceback): Caught exception when trying to load file of format [py]: cannot import name 'get_packages_share_directory' from 'ament_index_python.packages' (/opt/ros/humble/lib/python3.10/site-packages/ament_index_python/packages.py)

i dont know how to fix it can you provide me some documentation on ros2 in creating custom maps and robot model in gazebo