\newcommand*{\sagelisting}[1]{\tcbinputlisting{listing only,%
colback=codebg,%
coltext=codefg,%
+ enlarge bottom finally by=\baselineskip,%
+ enlarge top initially by=\baselineskip,%
left=2em,%
listing options={language=sage,style=sage},%
listing file=sage_listings/#1.listing}}