I would like to add another command to "Save as" menu that is generated by right clicking on selected text.

We have there "Plain Text" and after this I would like to add "Sagemath code". After clicking on it the text/code would be copied as plaintext with addition that spaces that represent multiplication would be replaced with "*".

For example if you "copy as plain text" this code 3 x^2 + 2 x + 1 you get string "3 x^2 + 2 x + 1" but I would like it to be 3*x^2 + 2*x + 1 because Sagemath recognizes only "*" as multiplication.

Sorry no code from me. I have no clues how to do it.