old_contents: from __future__ import absolute_import
  
  from builtins import range
  
  import autograd.util as au
  from autograd_forward.convenience_wrappers import forward_derivative
  
  def check_forward_grads(fun, *args):
      if not args:
          raise Exception("No args given")
      exact = tuple([forward_derivative(fun, i)(*args) for i in range(len(args))])
      args = [float(x) if isinstance(x, int) else x for x in args]
      numeric = au.nd(fun, *args)
      au.check_equivalent(exact, numeric)
  
  # This version of flatten should be merged into Autograd soon.
  def flatten(value):
      """Flattens any nesting of tuples, arrays, or dicts.
         Returns 1D numpy array and an unflatten function.
         Doesn't preserve mixed numeric types (e.g. floats and ints).
         Assumes dict keys are sortable."""
      try:
          vs = vspace(getval(value))
      except TypeError:
          raise Exception("Don't know how to flatten type {}".format(type(value)))
      return vs.flatten(value), vs.unflatten
  
new_contents: from __future__ import absolute_import
  
  from builtins import range
  
  from autograd.core import vspace, getval
  import autograd.util as au
  from autograd_forward.convenience_wrappers import forward_derivative
  
  def check_forward_grads(fun, *args):
      if not args:
          raise Exception("No args given")
      exact = tuple([forward_derivative(fun, i)(*args) for i in range(len(args))])
      args = [float(x) if isinstance(x, int) else x for x in args]
      numeric = au.nd(fun, *args)
      au.check_equivalent(exact, numeric)
  
  # This version of flatten should be merged into Autograd soon.
  def flatten(value):
      """Flattens any nesting of tuples, arrays, or dicts.
         Returns 1D numpy array and an unflatten function.
         Doesn't preserve mixed numeric types (e.g. floats and ints).
         Assumes dict keys are sortable."""
      try:
          vs = vspace(getval(value))
      except TypeError:
          raise Exception("Don't know how to flatten type {}".format(type(value)))
      return vs.flatten(value), vs.unflatten
  
subject: Fix util.py imports