code: public RootMethodRunResult getRunResultByRootMethodKey(String key) {
          if (key == null) {
              throw new NullPointerException();
          }
          for (RootMethodRunResult rootMethodRunResult : rootMethodRunResults) {
              if ((rootMethodRunResult.getRootMethod() != null)
                      && key.equals(rootMethodRunResult.getRootMethod().getKey())) {
                  return rootMethodRunResult;
              }
          }
          return null;
      }
docs: returns null if not found