anchor.diff:  
   ssh_open_connection_pre(S) -> S#state.servers /= [].
       
  -ssh_open_connection_args(S) -> [oneof(S#state.servers), S#state.data_dir].
  +ssh_open_connection_args(S) -> [oneof(S#state.servers), {var,data_dir}].
       
   ssh_open_connection(#srvr{address=Ip, port=Port}, DataDir) ->
       ok(ssh:connect(ensure_string(Ip), Port, 
  
positive.code: 
  
  do_prop_seq(DataDir) ->
      ?FORALL(Cmds,commands(?MODULE, #state{data_dir=DataDir}),
  	    begin
  		{H,Sf,Result} = run_commands(?MODULE,Cmds),
  		present_result(?MODULE, Cmds, {H,Sf,Result}, Result==ok)
  	    end).
  
  
negative.code:     do_prop_parallel(full_path(?SSH_DIR, CT_Config)).
  
  do_prop_parallel(DataDir) ->
      ?FORALL(Cmds,parallel_commands(?MODULE),
  	    begin
  		{H,Sf,Result} = run_parallel_commands(?MODULE,Cmds,[{data_dir,DataDir}]),
  		present_result(?MODULE, Cmds, {H,Sf,Result}, Result==ok)
  	    end).
  
  