anchor.diff:  -spec find_client(Address) -> Result
   	when
   		Address :: inet:ip_address(),
  -		Result :: {ok, #client{}} | {error, Reason}, 
  +		Result :: {ok, #client{}} | {error, Reason},
   		Reason :: not_found | term().
   %% @doc Find a client by IP address.
   %%
  
positive.code: 		N = erlang:unique_integer([positive]),
  		R = Pla#pla{last_modified = {TS, N}},
  		ok = mnesia:write(pla, R, write),
  		R 
  	end,
  	case mnesia:transaction(F) of
  		{atomic, #pla{name = Name} = Pla1} ->
  
negative.code: 				Buckets1 = lists:flatten([mnesia:read(bucket, B1, write)
  						|| B1 <- BucketRefs1]),
  				F2 = fun(B2) -> mnesia:delete(bucket, B2, write) end,
  				F3 = fun(B3) -> mnesia:write(bucket, B3, write) end,
  				case credit(Units, Amount, Buckets1) of
  					{0, DeleteRefs, Buckets2} ->
  						lists:foreach(F2, DeleteRefs),
  