anchor.diff:      simple_chain_state_transition_is_sane(undefined, UPI1, Repair1,
                                             undefined, UPI2).
   
  -simple_chain_state_transition_is_sane(Author1, UPI1, Repair1, Author2, UPI2) ->
  +simple_chain_state_transition_is_sane(_Author1, UPI1, Repair1, Author2, UPI2) ->
       put(why2, []),
       {KeepsDels, Orders} = mk(UPI1, Repair1, UPI2),
       NumKeeps = length([x || keep <- KeepsDels]),
  
positive.code:               upi=UPI_list2,
                repairing=Repairing_list2,
                dbg=Dbg2} = P2,
    RelativeToServer, RetrospectiveP) ->
   try
      put(why2, []),
      %% General notes:
  
negative.code:                    end,
      Disjoint_UPIs = ordsets:is_disjoint(ordsets:from_list(UPI1),
                                          ordsets:from_list(UPI2)),
      %% This if statement contains the only exceptions that we make to
      %% the judgement of simple_chain_state_transition_is_sane().
      if ToSelfOnly_p ->
  