code: private static HashMap<String, Double> strictCmmlInfoToHistogram(CMMLInfo strictCmml, String tagName) {
          final NodeList elements = strictCmml.getElementsByTagName(tagName);
          return contentElementsToHistogram(elements);
      }
docs: converts strict content math ml to a histogram for the given tagname, e.g., ci
  
  @param strictCmml
  @param tagName
  @return