code: def _kernel(
      self,
      q: Tensor,
      k: Tensor,
  ) -> Tensor:
      return pt.matmul(q, k.transpose(-1, -2)) / self.bandwidth
  
imports: from typing import Optional, List, Tuple, Union
  import math
  import numpy
  import torch
  from torch import Tensor, BoolTensor, nn
  from torch.nn import init, functional
  from tslib.nn.attention import Attention
  from tslib.nn.attention.posemb import SinusoidalPositionalEmbedding
label_desc: Use image node_id 1 for calling the ExpKernel obj's underlying member method code with example usage: obj._kernel(q, k) and returns: unknown