anchor.diff:  
   buildPythonPackage rec {
     pname = "cirq-core";
  -  version = "0.15.0";
  +  version = "1.0.0";
  +  format = "setuptools";
   
  -  disabled = pythonOlder "3.6";
  +  disabled = pythonOlder "3.7";
   
     src = fetchFromGitHub {
       owner = "quantumlib";
       repo = "cirq";
       rev = "v${version}";
  -    sha256 = "sha256-E36zXpv+9WBNYvv/shItS7Q34gYqUyADlqWd+m4Jpps=";
  +    hash = "sha256-KJ+z4zGrdGIXcGZzqHtWMf8aAzcn9CtltFawcHVldMQ=";
     };
   
     sourceRoot = "source/${pname}";
  
positive.code:     substituteInPlace requirements.txt \
        --replace "matplotlib~=3.0" "matplotlib" \
        --replace "networkx~=2.4" "networkx" \
        --replace "numpy~=1.16" "numpy" \
        --replace "sympy<1.10" "sympy"
    '';
  
    propagatedBuildInputs = [
  
negative.code: { lib
  , stdenv
  , buildPythonPackage
  , pythonOlder
  , fetchFromGitHub
  