code: def memcpy_dtoh(self, dest, src):
          
          if isinstance(src, drv.DeviceAllocation):
              drv.memcpy_dtoh(dest, src)
          else:
              dest = src
docs: perform a device to host memory copy
  
          :param dest: A numpy array in host memory to store the data
          :type dest: numpy.ndarray
  
          :param src: A GPU memory allocation unit
          :type src: pycuda.driver.DeviceAllocation