code: def _dump_qmc(self):
          
  
          ## open the h5 database
          with h5py.File(self.database.output, 'r') as io5:
  
              ## create an output file for writing
              self.files.qdump = os.path.join(self.dirs, self.name+".quartets.txt")
              with open(self.files.qdump, 'w') as qdump:
  
                  ## pull from db
                  for idx in xrange(0, self.params.nquartets, self._chunksize):
                      qchunk = io5["quartets"][idx:idx+self._chunksize, :]
                      quarts = [tuple(j) for j in qchunk if np.any(j)]
  
                      ## shuffle and format for qmc
                      np.random.shuffle(quarts)
                      chunk = ["{},{}|{},{}".format(*i) for i in quarts]
                      qdump.write("\n".join(chunk)+"\n")
docs: Writes the inferred quartet sets from the database to a text 
          file to be used as input for QMC. Quartets that had no information
          available (i.e., no SNPs) were written to the database as 0,0,0,0
          and are excluded here from the output.