Latex nested environment: align, linenomath, split - nested

Question

I'm writing a document with a lot of equations and I would like to create new environments to write my equations in. Only for convenience, it works without, but it is fastidious to type.
For single equations, I want to number the lines with lineo. With align environment, only use 1 equation number with the split environment, and number the lines. So I can do this in my document:
\usepackage[displaymath, mathlines]{lineno}
\linenumbers
...
\begin{linenomath}
\begin{equation}
\end{equation}
\end{linenomath}
and
\begin{linenomath}
\begin{align
\begin{split}
\end{split}
\end{align}
\end{linenomath}
This works, however, I'm trying to create new environments for it like this:
\newenvironment{my_equation}
{\begin{linenomath}
\begin{equation}
}
{
\end{equation}
\end{linenomath}
}
\newenvironment{my_align}
{\begin{linenomath}
\begin{align
\begin{split}
}
{
\end{split}
\end{align}
\end{linenomath}
}
These do not work. I got an error and the file won't compile. Am I doing things correctly? Which obvious solution did I miss?
Thanks for your help!

Answer 1

You can use the environ package:
\documentclass{article}
\usepackage{mathtools}
\usepackage[mathlines]{lineno}
\usepackage{environ}
\NewEnviron{my_equation}
{\begin{linenomath}
\begin{equation}
\BODY
\end{equation}
\end{linenomath}
}
\NewEnviron{my_align}
{\begin{linenomath}
\begin{align}
\begin{split}
\BODY
\end{split}
\end{align}
\end{linenomath}
}
\begin{document}
\begin{my_equation}
test
\end{my_equation}
\begin{my_align}
test
\end{my_align}
\end{document}