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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 create_roc(self):
 """Create a ROC file for this BAM file. 		raises: ValueError 		"""


        with (gzip.open(self._et_fn, "tr") if self.compress_intermediate_files else open(self._et_fn, "r")) as et_fo:
            with open(self._roc_fn, "w+") as roc_fo:
                self.et2roc(
                    et_fo=et_fo,
                    roc_fo=roc_fo,
                )