by a persistent ID.

      Like PERSID, except the persistent ID is popped off the stack (instead
      of being a string embedded in the opcode bytestream).  The persistent
      ID is passed to self.persistent_load(), and whatever object that
      returns is pushed on the stack.  See PERSID for more detail.
      z%repeated name %r at indices %d and %dz%repeated code %r at indices %d and %dFc