code: def testResolveInputGraphRef_ArtifactMultiMap(self):
      a1, a2 = self.create_artifacts(2)
      x1 = self.parse_input_spec(
          """
        input_graph_ref {
          graph_id: "graph_1"
          key: "x1_out"
        }
      """
      )
      x2 = self.parse_input_spec(
          """
        input_graph_ref {
          graph_id: "graph_1"
          key: "x2_out"
        }
      """
      )
      graph_1 = self.parse_input_graph(
          """
        nodes {
          key: "op_1"
          value {
            op_node {
              op_type: "DummyOp"
            }
            output_data_type: ARTIFACT_MULTIMAP
          }
        }
        result_node: "op_1"
      """
      )
      self.mock_graph_fn_result(
          graph_1, lambda inputs: {"x1_out": [a1], "x2_out": [a2]}
      )
  
      node_inputs = pipeline_pb2.NodeInputs(
          inputs={"x1": x1, "x2": x2}, input_graphs={"graph_1": graph_1}
      )
  
      result = node_inputs_resolver.resolve(
          self._mlmd_handle, node_inputs
      )
  
      self.assertEqual(result, [{"x1": [a1], "x2": [a2]}])
  
imports: from typing import Set
  from unittest import mock
  import tensorflow
  from tfx.orchestration.portable.input_resolution import exceptions
  from tfx.orchestration.portable.input_resolution import input_graph_resolver
  from tfx.orchestration.portable.input_resolution import node_inputs_resolver
  from tfx.orchestration.portable.input_resolution import partition_utils
  from tfx.orchestration.portable.input_resolution import channel_resolver
  from tfx.proto.orchestration import pipeline_pb2
  import tfx.types
  from tfx.types import channel_utils
  from tfx.utils import test_case_utils
  from google.protobuf import text_format
label_desc: Use image node_id 11 for calling the NodeInputsResolverTest obj's underlying member method code with example usage: obj.testResolveInputGraphRef_ArtifactMultiMap() without return types