code: def solve_lower_triangular(A, b):
      """Solves Ax=b when A is lower triangular."""
      return _solve_triangular_common(A, b, lower=True)
  
imports: from __future__ import print_function
  import numpy
  from scipy.linalg import solve_triangular
label_desc: Use image node_id 4 for calling a global function with example usage: solve_lower_triangular(A, b) and returns: _solve_triangular_common