code: def forward_chainerx(self, x):
      a, b = x
      # TODO(sonots): Support transa and transb in ChainerX
      if self.transa or self.transb or self.transc:
          return chainer.Fallback
      # TODO(sonots): Support dtype promotion in ChainerX
      if a.dtype != b.dtype:
          return chainer.Fallback
      # TODO(sonots): Support ndim > 2 in ChainerX
      if a.ndim != 2 or b.ndim != 2:
          return chainer.Fallback
      # TODO(niboshi): Support it
      if self.dtype is not None and self.dtype != a.dtype:
          return chainer.Fallback
      return (chainerx.dot(a, b),)
  
imports: import warnings
  import numpy
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  import chainer.functions
  from chainer import utils
  from chainer.utils import type_check
  import chainerx
label_desc: Use image node_id 3 for calling the MatMul obj's underlying member method code with example usage: obj.forward_chainerx(x) and returns: chainerx, chainer, chainer, chainer, chainer