code: def _lower2upper(lb):
      """
      Convert lower triangular banded matrix to upper banded form.
  
      INPUTS:
         lb  -- a lower triangular banded matrix
  
      OUTPUTS: ub
         ub  -- an upper triangular banded matrix with same entries
                as lb
      """
  
      ub = np.zeros(lb.shape, lb.dtype)
      nrow, ncol = lb.shape
      for i in range(lb.shape[0]):
          ub[nrow - 1 - i, i:ncol] = lb[i, 0 : (ncol - i)]
          ub[nrow - 1 - i, 0:i] = lb[i, (ncol - i) :]
      return ub
  
imports: import numpy
  import numpy.linalg
  from scipy.linalg import solveh_banded
  from scipy.optimize import golden
  from models import _hbspline
  import warnings
label_desc: Use image node_id 3 for calling a global function with example usage: _lower2upper(lb) and returns: ub