code: def to_transfac(self):
          
          m = "%s\t%s\t%s\n" % ("DE", self.id, "unknown")
          for i, (row, cons) in enumerate(zip(self.pfm, self.to_consensus())):
              m += "%i\t%s\t%s\n" % (i, "\t".join([str(int(x)) for x in row]), cons)
          m += "XX"
          return m
docs: Return motif formatted in TRANSFAC format
          
          Returns
          -------
          m : str
              String of motif in TRANSFAC format.