nix: python devshell

flake.nix

@@ -0,0 +1,37 @@
+{
+  description = "A very basic flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs =  { self, nixpkgs }: {
+    devShells.x86_64-linux.default =
+      let
+      insecure-package-overlay = final: prev: {
+        nixpkgs.config.permittedInsecurePackages = [
+          # Add the full name and version of the package here
+          "python-2.7.18.8-env"
+          # "another-insecure-package-2.0"
+        ];
+      };
+        pkgs = import nixpkgs {
+          system = "x86_64-linux";
+          overlays = [insecure-package-overlay];
+        };
+        pyenv = pkgs.python3.withPackages (ps: [
+    ps.gevent      # Version 1.2.1 from pinned nixpkgs
+    ps.pygame      # Version 1.9.3 from pinned nixpkgs
+    ps.numpy   # Our custom-versioned NumPy
+  ]);
+
+      in
+      pkgs.mkShell {
+        buildInputs = [
+          
+pyenv
+       
+        ];
+      };
+  };
+}