docs: def create_et(self):
          """Create a et file for this BAM file (mapping information about read tuples).
  
  		raises: ValueError
  
  		"""
  
          with (gzip.open(self._es_fn, "tr") if self.compress_intermediate_files else open(self._es_fn, "r")) as es_fo:
              with (gzip.open(self._et_fn, "tw+")
                    if self.compress_intermediate_files else open(self._et_fn, "w+")) as et_fo:
                  self.es2et(
                      es_fo=es_fo,
                      et_fo=et_fo,
                  )