code: def value(self):
          
  
          def validate(node_value):
              if hasattr(node_value, 'validate'):
                  node_value.validate()
              return node_value
  
          if 'value' in self.node:
              return validate(self.node['value'])
          return self
docs: Return the node value, if we're a leaf node.
  
          Examples:
              >>> c = Configuration("test")
              >>> c['x'] = { "y" : { "value" : None }, "z" : { "value" : 2 }}
              >>> c['x']['y'].value == None
              True
              >>> c['x']['z'].value
              2
              >>> c['x'].value
              TEST_X_Y=null
              TEST_X_Z=2