how to add a shortcut to desktop by a shell command or a Python API or a C API?

[wk]

Hi,
   My enviroment is centos7.4 and default KDE desktop.
   In Plasma document, it said: "Right clicking on an application entry brings 
you some options for the entry: Add to Favorites, Add to Panel or Add to 
Desktop. "
   My question is: how to add a shortcut to desktop by a shell command or a 
Python API or a C API?

thank you.
w.k