code: def _soln2str(self, soln, fancy=False):
          
          chars = list()
          for r in range(1, 10):
              for c in range(1, 10):
                  if fancy and c in (4, 7):
                      chars.append("|")
                  chars.append(self._get_val(soln, r, c))
              if fancy and r != 9:
                  chars.append("\n")
                  if r in (3, 6):
                      chars.append("---+---+---\n")
          return "".join(chars)
docs: Convert a Sudoku solution point to a string.