code: def _inv_cov(self) -> torch.Tensor:
      return torch.bmm(
          self.inv_cov_factor, self.inv_cov_factor.transpose(1, 2)
      )
  
imports: from torch import nn
  import torch
label_desc: Use image node_id 2 for calling the GMMModel obj's underlying member method code with example usage: obj._inv_cov() and returns: torch