Adding font size to already defined command

I am using the answer here to add source code to my beamer (usually inline), as:

usepackage{xcolor}
definecolor{light-gray}{gray}{0.95}
newcommand{code}[1]{colorbox{light-gray}{texttt{#1}}}

But then some lines of code cannot fit to a single line, so I have to reduce the font size to fit.

Then I add a font size to the code command like:

newcommand{code}[1]{colorbox{light-gray}{texttt{#1}[10pt]{fontsize{#2}{#1}selectfont #3}}}

This doesn’t work. What’s the correct way of doing this?

newcommand{code}[2][]{colorbox{light-gray}{texttt{#1#2}}}

code{Some code to typeset}

code[tiny]{Some code to typeset}