code: def _triangular_inverse(A, upper=False):
      eye = torch.eye(A.size(-1), dtype=A.dtype, device=A.device)
      return torch.linalg.solve_triangular(A, eye, upper=upper)
  
imports: import abc
  import torch
  from linear_operator.operators import CholLinearOperator, TriangularLinearOperator
  from linear_operator.utils.cholesky import psd_safe_cholesky
  from ..distributions import MultivariateNormal
  from ._variational_distribution import _VariationalDistribution
label_desc: Use image node_id 1 for calling a global function with example usage: _triangular_inverse(A, upper) and returns: torch