code: def _tril(x, k=0):
      _tril_kernel(k, x)
      return x
  
file_path: cupy/cupy/linalg/_util.py
imports: import os
  import numpy
  from numpy import linalg
  import cupy
  import cupy._util
  from cupy import _core
  import cupyx
label_desc: Use image node_id 9 for calling a global function with example usage: _tril(x, k) and returns: x