anchor.diff:  , pymatgen
   , pytest
   , pythonOlder
  +, pythonAtLeast
   , requests
   , scipy
   , toolz
  
positive.code:   pname = "atomman";
    format = "setuptools";
  
    disabled = pythonOlder "3.6";
  
    src = fetchFromGitHub {
      owner = "usnistgov";
  
negative.code:   checkPhase = ''
      # pytestCheckHook doesn't work
      pytest tests -k "not test_rootdir and not test_version \
        and not test_atomic_mass and not imageflags \
        and not test_build_unit and not test_set_and_get_in_units \
        and not test_set_literal and not test_scalar_model " \
        --ignore tests/plot/test_interpolate.py \
        --ignore tests/tools/test_vect_angle.py
    '';
  
    pythonImportsCheck = [
  