func: function workOrderCallback(address _woid,string _stdout, string _stderr, string _uri) public
  	 {
  		 require(iexecHubInterface.isWoidRegistred(_woid));
  		 require(!isCallbackDone(_woid));
  		 m_callbackDone[_woid] = true;
  		 require(WorkOrder(_woid).m_status() == IexecLib.WorkOrderStatusEnum.COMPLETED);
  		 require(WorkOrder(_woid).m_resultCallbackProof() == keccak256(_stdout,_stderr,_uri));
  		 address callbackTo =WorkOrder(_woid).m_callback();
  		 require(callbackTo != address(0));
  		 require(IexecCallbackInterface(callbackTo).workOrderCallback(
  			 _woid,
  			 _stdout,
  			 _stderr,
  			 _uri
  		 ));
  		 emit WorkOrderCallbackProof(_woid,WorkOrder(_woid).m_requester(),WorkOrder(_woid).m_beneficiary(),callbackTo,tx.origin,_stdout,_stderr,_uri);
  	 }