code: @Override
      String sourceContentFor(String aSource, Boolean nullOnMissing) {
          for (int i = 0; i < this._sections.size(); i++) {
              ParsedSection section = this._sections.get(i);
              String content = section.consumer.sourceContentFor(aSource, true);
              if (content != null) {
                  return content;
              }
          }
          if (nullOnMissing != null && nullOnMissing) {
              return null;
          } else {
              throw new RuntimeException("\"" + aSource + "\" is not in the SourceMap.");
          }
      }
docs: Returns the original source content. The only argument is the url of the original source file. Returns null if no original source content is
  available.