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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 setup(self):
 """ interface with vrtsexplorer to capture veritas related data """

        r = self.call_ext_prog(self.get_option("script"))
        if r['status'] == 0:
            tarfile = ""
            for line in r['output']:
                line = line.strip()
                tarfile = self.do_regex_find_all(r"ftp (.*tar.gz)", line)
            if len(tarfile) == 1:
                self.add_copy_spec(tarfile[0])