code: def auc(x: Tensor, y: Tensor) -> Tensor:
      if torch.any(x.diff() < 0):
          raise ValueError("'x' must be given in ascending order")
      return torch.trapezoid(y, x)
  
file_path: pytorch_geometric/torch_geometric/explain/metric/fidelity.py
imports: from typing import Tuple
  import torch
  from torch import Tensor
  from torch_geometric.explain import Explainer, Explanation
  from torch_geometric.explain.config import ExplanationType, ModelMode
label_desc: Use image node_id 4 for calling a global function with example usage: auc(x, y) and returns: torch