  from nose.tools import assert_equal
  
  
  class TestBstValidate(object):
  
      @raises(Exception)
      def test_bst_validate_empty(self):
 
</s>
from nose.tools import raises
  from nose.tools import assert_equal
from nose.tools import raises
  
  
  class TestBstValidate(object):
  
      @raises(Exception)
      def test_bst_validate_empty(self):
add keep keep keep keep keep keep
 Polish bst validate challenge and solution (#83)

Update constraints, test cases, tests, algorithm discussion, and code.
graphs_trees/bst_validate/test_bst_validate.py