anchor.diff:  
   buildPythonPackage rec {
     pname = "imap-tools";
  -  version = "0.49.1";
  +  version = "0.50.0";
   
     disabled = isPy27;
   
  
positive.code:     "test_connectio"
      "test_attributes"
      "test_live"
      # logic operator tests broken in 0.49.0
      # https://github.com/ikvk/imap_tools/issues/143
      "test_logic_operators"
    ];
  
    pythonImportsCheck = [ "imap_tools" ];
  
negative.code:     owner = "ikvk";
      repo = "imap_tools";
      rev = "v${version}";
      sha256 = "sha256-4OMWLWvNRg7z4KAAkB1l5YaWILFwIepZOWhBd64SGWI=";
    };
  
    checkInputs = [
  