new_contents: '''
      CPU sensor plugin
  
      Generates the CPU usage stats
  '''
  from ptop.core import Plugin
  import psutil
  
  class CPUSensor(Plugin):
      def __init__(self,**kwargs):
          super(CPUSensor,self).__init__(**kwargs)
  
      # overriding the update method
      def update(self):
          # there will be two parts of the returned value, one will be text and other graph
          # there can be many text (key,value) pairs to display corresponding to each key
          self.currentValue['text'] = {}
          # there will be one averaged value
          self.currentValue['graph'] = {'percentage' : ''}
          # cpu usage
          cpu_usage = psutil.cpu_percent(percpu=True)
          num_cores = len(cpu_usage)
          self.currentValue['text']['number_of_cores'] = str(num_cores)
          for ctr in range(num_cores):
              self.currentValue['text']['core{0}'.format(ctr+1)] = cpu_usage[ctr]
          # average cpu usage
          self.currentValue['graph']['percentage'] = sum(cpu_usage)/num_cores
  
  
  cpu_sensor = CPUSensor(name='CPU',sensorType='chart',interval=0.5)
  
  
  
subject: update : minor changes