old_contents: """This module contains some general purpose utilities that are used across
  SymPy.
  """
  from iterables import (flatten, group, take, subsets,
      variations, numbered_symbols, cartes, capture, dict_merge,
      postorder_traversal, preorder_traversal, interactive_traversal,
      prefixes, postfixes, sift, topological_sort)
  
  from lambdify import lambdify
  from source import source
  
  from decorator import threaded, xthreaded
  
  from runtests import test, doctest
  
  from cythonutils import cythonized
  from timeutils import timed
  
  from misc import default_sort_key
  
new_contents: """This module contains some general purpose utilities that are used across
  SymPy.
  """
  from iterables import (flatten, group, take, subsets,
      variations, numbered_symbols, cartes, capture, dict_merge,
      postorder_traversal, preorder_traversal, interactive_traversal,
      prefixes, postfixes, sift, topological_sort, unflatten)
  
  from lambdify import lambdify
  from source import source
  
  from decorator import threaded, xthreaded
  
  from runtests import test, doctest
  
  from cythonutils import cythonized
  from timeutils import timed
  
  from misc import default_sort_key
  
subject: add unflatten to namespace