This may not be considered as an "answer" and I should have reponded as a comment but I do not have enough reputation to do so. If you want to run a simple Python command in R you can use py_run_string.

library(reticulate)
py_run_string("print('Hello World')")

Alternatively, you can use import_builtins

main <- import_main()
builtins <- import_builtins()
builtins$print('Hello world')

The overview page of the reticulate library has good information, and I think it will address majority of your questions.