code: def __init__(self):
      if not _cupy_avail:
          raise RuntimeError(
              "HostPinnedMemory cannot be used: "
              + "Cupy is not available."
          )
      self.size = 0
      self.memory = None
  
imports: import ctypes
  import mpi4py.MPI
  import numpy
  from chainermn.communicators import _communication_utility
  import chainer.backends
  import chainerx
label_desc: Use image node_id 1 to create a new HostPinnedMemory object from inherited base classes: object with example: obj = HostPinnedMemory()