code: def flatten_list_of_lists(L):
      """Flattens a list of lists to return a single list of objects."""
      return [item for sublist in L for item in sublist]
  
imports: from __future__ import print_function
  from __future__ import division
  import numpy
  from scipy.sparse import dok_matrix
  from scipy.linalg import solve_triangular
label_desc: Use image node_id 26 for calling a global function with example usage: flatten_list_of_lists(L) and returns: unknown