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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def write_pre_script(self,fh):
 """ Write the pre script for the job, if there is one @param fh: descriptor of open DAG file. """

    if self.__pre_script:
      fh.write( 'SCRIPT PRE ' + str(self) + ' ' + self.__pre_script + ' ' +
        ' '.join(self.__pre_script_args) + '\n' )