To make a panel run a Rhino command ‘RunPythonScript’ in the Rhinos’ Command Line. The RunPythonScript command is used to execute script that were loaded into the Python engine. The RunScript dialog box will display a file dialog box. Select a Python file (PerfFacadePanelUI.py) to run in Rhino. Simply select the python file and hit OK. The Python script will run. Please, watch the video.
The main advantage of python scripting is an easy-to-use API that runs across multiple platforms. However, cross-platform functionality may cause some bugs that are hard to identify on macOS and Windows. The script file is shipped 'as is' in the form of open source. You are free to modify it as you wish. Directly edit the source code is the only way to improve the script.