minted uses the package fancyvrb to create the environment. fancyvrb uses a modification of trivlist. So you can have to modify the trivlist.
One possibility is shown below. Here I created a new key belowskip.
EDIT
In combination width \newminted it also works (see comment below):
% pdflatex --shell-escape
\documentclass{article}
\usepackage{minted}
\makeatletter
\newlength\minted@belowskip
\define@key{minted@opt}{belowskip}[\@topsepadd]
{\setlength{\minted@belowskip}{#1}}
\def\minted@endparenv{%
\addpenalty\@endparpenalty\addvspace\minted@belowskip\@endpetrue}
\def\FV@EndList{%
\FV@ListProcessLastLine
\FV@EndListFrame
\minted@endparenv
\endgroup
\@endpetrue}
\makeatother
\newminted{python3}{linenos=true, belowskip=4cm}
\begin{document}
\begin{python3code}
print("Hello world")
\end{python3code}
Some text
\begin{python3code}
print("Hello world")
\end{python3code}
Some text
\end{document}
Orig
% pdflatex --shell-escape
\documentclass{article}
\usepackage{minted}
\makeatletter
\newlength\minted@belowskip
\define@key{minted@opt}{belowskip}[\@topsepadd]
{\setlength{\minted@belowskip}{#1}}
\def\minted@endparenv{%
\addpenalty\@endparpenalty\addvspace\minted@belowskip\@endpetrue}
\def\FV@EndList{%
\FV@ListProcessLastLine
\FV@EndListFrame
\minted@endparenv
\endgroup
\@endpetrue}
\makeatother
\begin{document}
\begin{minted}[belowskip=4cm]{python}
print("Hello world")
\end{minted}
Some text
\begin{minted}[belowskip=0pt]{python}
print("Hello world")
\end{minted}
Some text
\end{document}
`\newminted{python3}{linenos=true, belowskip=0pt}
\begin{python3code} ... `
– pg-robban Dec 04 '11 at 20:28\newmindet. – Marco Daniel Dec 04 '11 at 20:53package calc error 'xkv@tempa@toks' invalid at this point.But the MWE seems to be working so I'll accept this answer. Thank you! – pg-robban Dec 04 '11 at 21:13calcis loaded byminteditself. I can't from that output what the conflict is. But if you wanted to track it down, you could probably use justcalcwith whatever your other packages are to minimize the bug. – Jason Hemann Mar 17 '18 at 20:09