code: public String extractToString(final String separator, final String endSeparator) throws DevFailed {
          logger.debug(LOG_EXTRACTING, this);
          return attributeImpl.extractToString(separator, endSeparator);
      }
docs: Extract data and format it as followed :\n SCALAR: ex: 1 SPECTRUM: one
  line separated by separator. \n ex: 1 3 5 IMAGE: x lines and y colums
  separated by endSeparator.\n ex: 3 5 8 5 6 9
  
  @param separator
  @param endSeparator
  @return
  @throws DevFailed