code: def test_empty_fused_std_aggregation():
      aggrs = [
          aggregation_resolver(aggr) for aggr in ["mean", "var", "std"]
      ]
      aggr = FusedAggregation(aggrs)
  
      x = torch.empty(0, 6).reshape(0, 6)
      index = torch.empty(0, dtype=torch.long)
  
      out = torch.cat(aggr(x, index, dim_size=5), dim=-1)
      assert out.size() == (5, 18)
      assert float(out.abs().sum()) == 0.0
  
imports: import pytest
  import torch
  from torch_geometric.nn.aggr.fused import FusedAggregation
  from torch_geometric.nn.resolver import aggregation_resolver
  from torch_geometric.profile import benchmark
label_desc: Use image node_id 2 for calling a global function with example usage: test_empty_fused_std_aggregation() without return types