code: def forward(self, x_dict, edge_index_dict, *args) -> torch.Tensor:
      return x_dict["paper"].mean().view(-1)
  
file_path: pytorch_geometric/test/explain/test_hetero_explainer.py
imports: import pytest
  import torch
  from torch_geometric.explain import DummyExplainer, Explainer, HeteroExplanation
  from torch_geometric.explain.config import ExplanationType
label_desc: Use image node_id 1 for calling the DummyModel obj's underlying member method code with example usage: obj.forward(x_dict, edge_index_dict) and returns: x_dict