code: def ptr(self, offset=0):
      return ctypes.c_void_p(self.memory.ptr + offset)
  
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 3 for calling the HostPinnedMemory obj's underlying member method code with example usage: obj.ptr(offset) and returns: ctypes