code: def _fields_valid(self, d):
          
          if 'DATATYPE' not in d:
              return False
  
          datatype = d['DATATYPE']
          if datatype == 'HOSTPERFDATA':
              fields = self.GENERIC_FIELDS + self.HOST_FIELDS
          elif datatype == 'SERVICEPERFDATA':
              fields = self.GENERIC_FIELDS + self.SERVICE_FIELDS
          else:
              return False
  
          for field in fields:
              if field not in d:
                  return False
  
          return True
docs: Verify that all necessary fields are present
  
          Determine whether the fields parsed represent a host or
          service perfdata. If the perfdata is unknown, return False.
          If the perfdata does not contain all fields required for that
          type, return False. Otherwise, return True.