code: def shock_sol(x):
      eps = 1e-3
      k = np.sqrt(2 * eps)
      return np.cos(np.pi * x) + erf(x / k) / erf(1 / k)
  
imports: import sys
  import numpy
  from numpy.testing import assert_, assert_array_equal, assert_allclose, assert_equal
  from pytest import raises
  from scipy.sparse import coo_matrix
  from scipy.special import erf
  from scipy.integrate._bvp import modify_mesh, estimate_fun_jac, estimate_bc_jac, compute_jac_indices, construct_global_jac, solve_bvp
label_desc: Use image node_id 29 for calling a global function with example usage: shock_sol(x) and returns: unknown