docs: 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,
                  )