anchor.diff:  , withTorch ? false
   , pytorch
   , withPyscf ? false
  -, pyscf ? null
  +, pyscf
   , withScikitQuant ? false
   , scikit-quant ? null
   , withCplex ? false
  
positive.code:     owner = "Qiskit";
      repo = "qiskit-aqua";
      rev = version;
      hash = "sha256-fptyqPrkUgl3UjtlEmDYORdX/SsONxWozQGEs/EahmU=";
    };
  
    # Optional packages: pyscf (see below NOTE) & pytorch. Can install via pip/nix if needed.
  
negative.code: 
  buildPythonPackage rec {
    pname = "qiskit-aqua";
    version = "0.9.5";
  
    disabled = pythonOlder "3.6";
  
  