cpm 12.0.0

Error log

The package failed to build. The error log from opam follows.

Opam plugin "depext" may require upgrading/reinstalling. Reinstall the plugin on the current switch? [Y/n] y
The following actions will be performed:
  - recompile opam-depext 1.2.3

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-> retrieved opam-depext.1.2.3  (cached)
-> removed   opam-depext.1.2.3
-> installed opam-depext.1.2.3
Done.

<><> opam-depext.1.2.3 installed successfully <><><><><><><><><><><><><><><><><>
=> opam-depext is unnecessary when used with opam >= 2.1. Please use opam install directly instead
# Run eval $(opam env) to update the current shell environment

<><> Carrying on to "opam depext -viy lbvs_consent.2.0.0 topkg.1.0.7 stdlib-shims.0.3.0 seq.base result.1.5 qcheck-ounit.0.17 qcheck-core.0.17 qcheck.0.17 ppx_derivers.1.2.1 parmap.1.2.1 ounit2.2.2.6 ocplib-endian.1.2 ocamlfind.1.9.6 ocamlbuild.0.15.0 ocaml-migrate-parsetree.1.8.0 obuild.0.1.11 num.1.5-1 minivpt.2.0.0 lwt.5.7.0 logs.0.7.0 extunix.0.2.0 dune-configurator.1.0.0 dune.1.11.4 dolog.3.0 dokeysto_camltc.4.0.0 dokeysto.4.0.1 cppo.1.6.9 cpm.12.0.0 conf-zlib.1 conf-rdkit.1 conf-python-2-7.1.2 conf-pkg-config.3 conf-openbabel.0.1 conf-boost.1 conf-bash.1 conf-autoconf.0.2 camlzip.1.11 camltc.0.9.8 bitv.1.3 batteries.3.5.1 base-bytes.base" 

Since version 2.1, opam now handles external dependencies alongside OCaml ones, and the `depext` plugin interface is provided for backwards compatibility only. Consider using your usual `opam install` command to install both OCaml and system dependencies, or `opam install <pkg> --depext-only` if you want to only install external dependencies.
# Detecting depexts using vars: arch=x86_64, os=linux, os-distribution=debian, os-family=debian
[ERROR] No solution for lbvs_consent.2.0.0 & topkg.1.0.7 & stdlib-shims.0.3.0 & seq.base & result.1.5 & qcheck-ounit.0.17 & qcheck-core.0.17 & qcheck.0.17 & ppx_derivers.1.2.1 & parmap.1.2.1 & ounit2.2.2.6 & ocplib-endian.1.2 & ocamlfind.1.9.6 & ocamlbuild.0.15.0 & ocaml-migrate-parsetree.1.8.0 & obuild.0.1.11 & num.1.5-1 & minivpt.2.0.0 & lwt.5.7.0 & logs.0.7.0 & extunix.0.2.0 & dune-configurator.1.0.0 & dune.1.11.4 & dolog.3.0 & dokeysto_camltc.4.0.0 & dokeysto.4.0.1 & cppo.1.6.9 & cpm.12.0.0 & conf-zlib.1 & conf-rdkit.1 & conf-python-2-7.1.2 & conf-pkg-config.3 & conf-openbabel.0.1 & conf-boost.1 & conf-bash.1 & conf-autoconf.0.2 & camlzip.1.11 & camltc.0.9.8 & bitv.1.3 & batteries.3.5.1 & base-bytes.base:   * Missing dependency:
            - conf-python-2-7
            depends on the unavailable system package 'python2.7'. Use `--no-depexts' to attempt installation anyway, or it is possible that a depext package name in the opam file is incorrect.


Command failed: opam --cli=2.1 list --readonly --external '--resolve=lbvs_consent.2.0.0,topkg.1.0.7,stdlib-shims.0.3.0,seq.base,result.1.5,qcheck-ounit.0.17,qcheck-core.0.17,qcheck.0.17,ppx_derivers.1.2.1,parmap.1.2.1,ounit2.2.2.6,ocplib-endian.1.2,ocamlfind.1.9.6,ocamlbuild.0.15.0,ocaml-migrate-parsetree.1.8.0,obuild.0.1.11,num.1.5-1,minivpt.2.0.0,lwt.5.7.0,logs.0.7.0,extunix.0.2.0,dune-configurator.1.0.0,dune.1.11.4,dolog.3.0,dokeysto_camltc.4.0.0,dokeysto.4.0.1,cppo.1.6.9,cpm.12.0.0,conf-zlib.1,conf-rdkit.1,conf-python-2-7.1.2,conf-pkg-config.3,conf-openbabel.0.1,conf-boost.1,conf-bash.1,conf-autoconf.0.2,camlzip.1.11,camltc.0.9.8,bitv.1.3,batteries.3.5.1,base-bytes.base' --color=never returned 20