[PyMOL] How to send pymol command to pymol by python interpreter

[Takefumi Sora]

Dear Pymol users

I launch Pymol in my python program.
After that, I can't change objects in pymol in my
python program. In short I do not know how to
send pymol command (ex cmd.do("show cartoon")) to 
Pymol not by directly input in pymol external command line 
but by python interpreter.

Does anybody know how to do this ?

Thank you.
Takefumi SORA