❯ nix-build -A ansible_2_6
error: Package ‘python3.7-ansible-2.9.9’ in /home/hexa/git/nixos/release-20.03/pkgs/tools/admin/ansible/default.nix:30 is marked as insecure, refusing to evaluate.


Known issues:
 - Ansible 2.6 is End-of-Life since 2019/11/06 and affected by multiple CVEs.

You can install it anyway by whitelisting this package, using the
following methods:

a) for `nixos-rebuild` you can add ‘python3.7-ansible-2.9.9’ to
   `nixpkgs.config.permittedInsecurePackages` in the configuration.nix,
   like so:

     {
       nixpkgs.config.permittedInsecurePackages = [
         "python3.7-ansible-2.9.9"
       ];
     }

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
‘python3.7-ansible-2.9.9’ to `permittedInsecurePackages` in
~/.config/nixpkgs/config.nix, like so:

     {
       permittedInsecurePackages = [
         "python3.7-ansible-2.9.9"
       ];
     }


(use '--show-trace' to show detailed location information)