Error with HeteroData nn captum explainer

[aihiangng]

I followed the sample given here: https://github.com/pyg-team/pytorch_geometric/blob/master/torch_geometric/nn/models/captum.py#L326

from captum.attr import IntegratedGradients

from torch_geometric.data import HeteroData
from torch_geometric.nn import HeteroConv
from torch_geometric.nn import (captum_output_to_dicts,
                                to_captum_model, to_captum_input)

# data = HeteroData(...)
# model = HeteroConv(...)
...  # Train the model.

# Explain predictions for node `10`:
mask_type="edge"
metadata = data.metadata
output_idx = 10
captum_model = to_captum_model(model, mask_type, output_idx, metadata)
inputs, additional_forward_args = to_captum_input(data.x_dict,
                                    data.edge_index_dict, mask_type)

ig = IntegratedGradients(captum_model)
ig_attr = ig.attribute(inputs=inputs,
                       target=int(y[output_idx]),
                       additional_forward_args=additional_forward_args,
                       internal_batch_size=1)
edge_attr_dict = captum_output_to_dicts(ig_attr, mask_type, metadata)

And i get this error message.

[aihiangng]

ok solved it, should have been

metadata = data.metadata() # add the brackets