code: def startprocessmonitor(self, process_name, interval=2):
          
          if process_name in self._process_stats:
              # Stop previously running instance
              # At any point, only one process name can be tracked
              # If an instance already exist, then stop it
              self._process_stats[process_name].stop()
          # Create an instance of process stat
          self._process_stats[process_name] = ProcessStats(process_name, interval)
          # start monitoring the process
          self._process_stats[process_name].start()
          return 1
docs: Start memory and CPU monitoring, with the time interval between
          each process scan
  
          @param process_name: Process name, ex: firefox-bin.
          @type process_name: string
          @param interval: Time interval between each process scan
          @type interval: double
  
          @return: 1 on success
          @rtype: integer