code: public static boolean isSupportedFormat(String format) {
  	for (int i=0;i<MSExcelWriter.VALID_FORMAT.length;i++) {
  		if (VALID_FORMAT[i].equals(format)) {
  			return true;
  		}
  	}
  return false;
  }
docs: Checks if format is supported
  
  @param format String describing format
  
  @return true, if supported, false if not