  from __future__ import print_function
  from nose.tools import assert_equal
  
  
  class TestDfs(object):
  
 
</s> remove     "from __future__ import print_function\n",
 </s> add  </s> remove     "from __future__ import print_function\n",
 </s> add  </s> remove     "%run ../utils/captured_output.py"
 </s> add     "%run ../utils/results.py"

  from nose.tools import assert_equal
  
  
  class TestDfs(object):
  
replace keep keep keep keep keep
 Reworked tree dfs unit tests. 
graphs_trees/tree_dfs/test_dfs.py