> First it’s necessary to install OCaml and Opam. Opam is the default package manager for OCaml projects.<p><pre><code> $ sudo apt install opam
...list of packages, including several python 2 packages, darcs, and mercurial ---
After this operation, 451 MB of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.
</code></pre>
Python 2 ? In 2021?<p>Also, darcs? <i>And</i> mercurial?