'Add a new CpuDiagnostics object
:param id: The virtual cpu number (Integer)
:param time: CPU Time in nano seconds (Integer)
:param utilisation: CPU utilisation in percentages (Integer)'

def add_cpu(self, id=None, time=None, utilisation=None):

    self.num_cpus += 1
    self.cpu_details.append(CpuDiagnostics(id=id, time=time, utilisation=utilisation))
