code: def write_pre_script(self,fh):
      
      if self.__pre_script:
        fh.write( 'SCRIPT PRE ' + str(self) + ' ' + self.__pre_script + ' ' +
          ' '.join(self.__pre_script_args) + '\n' )
docs: Write the pre script for the job, if there is one
      @param fh: descriptor of open DAG file.