IDLE is an open-source IDE for Python.  Being open-source, it is completely free, so It can be downloaded and installed onto your own computers from here:

https://www.python.org/downloads/

Run IDLE on the school computers

1. Click the Start button (bottom-left of your screen).
2. Click All Programs.
3. Scroll down to the Python 3.x folder
   • Click the folder to open it.
4. Click IDLE (Python 3.x 32-bit).
5. Once IDLE loads, click File, then New File to open a new script window.

Open Python files

DO NOT double click your file, this will run the program once with a black background and then close it again.

1. Open IDLE.
2. From the File drop-down menu, choose Open File.

or

1. Find your Python file in the file manager.
2. Right-click it
3. Choose Edit with IDLE, then Edit with IDLE 3.x.