code: def calloc(self, sim_nmemb, sim_size):
          
          raise NotImplementedError("%s not implemented for %s" % (self.calloc.__func__.__name__,
                                                                   self.__class__.__name__))
docs: A somewhat faithful implementation of libc `calloc`.
  
          :param     sim_nmemb: the number of elements to allocated
          :param     sim_size: the size of each element (in bytes)
          :returns:  the address of the allocation, or a NULL pointer if the allocation failed