func_code: def swap_unique_keys_values(d):
      l = [(k, v) for k, v in d]
      z = []
      for c in l:
          if l.count(c[1]) == 1:
              z.append(c[1])
      d1 = {v: k for k, v in list(d.items()) if v in z}
      return d1