reticulate segfault and accompanying detective work

gistfile1.txt

> library(reticulate)
> py_config()

 *** caught segfault ***
address 0x8, cause 'memory not mapped'

Traceback:
 1: py_run_string_impl(paste0("import sys; sys.path.append('", system.file("python",     package = "reticulate"), "')"))
 2: initialize_python(required_module, use_environment)
 3: ensure_python_initialized()
 4: py_config()
 
 
> Sys.which('python')
                                                                    python 
"/nix/store/m2br92794yw09hjwh3vzadbphckagmzv-python3-3.7.3-env/bin/python" 
> system.file("python", package="reticulate")
[1] "/nix/store/v64aywkbbr4qj92xv19fxmhdv66icl3q-r-reticulate-1.10/library/reticulate/python"

rPackages.nix

{ config, pkgs, ...}:

  with pkgs;
  let myPackages =
    with rPackages;
      [
        reticulate
        keras
        tensorflow
      ];
    in
  let
    myR = rWrapper.override
    {
      packages = myPackages;
    };
  in {
       environment.systemPackages = [ myR ];
     }

shell.nix

with import <nixpkgs> {};

(python3.withPackages (ps: 
  [
    ps.Keras
    ps.tensorflow
  ]
 )
).env