class_docstr: Transform from unconstrained matrices to lower-triangular matrices with
  all ones diagonals.
code: def _call(self, x):
      return x.tril(-1) + torch.eye(
          x.size(-1), device=x.device, dtype=x.dtype
      )
  
file_path: pyro/pyro/distributions/transforms/unit_cholesky.py
imports: import torch
  from torch.distributions import constraints
  from torch.distributions.transforms import Transform
  from pyro.distributions.constraints import unit_lower_cholesky
label_desc: Use image node_id 2 for calling the UnitLowerCholeskyTransform obj's underlying member method code with example usage: obj._call(x) and returns: unknown