code: public static int getStart(String headerLine) throws InvalidObjectException {
          String str = getHeaderInfo("start", headerLine);
          if (str == null) {
              throw new InvalidObjectException("WigFile format, it could not find 'start' in the header line");
          }
          return Integer.parseInt(str);
      }
docs: Extract the 'start' value from the given Wig header line.
  
  @param headerLine    Header line where to look for the 'start'
  @return              Start value