parameters: (self)
return_statement: return self.left is None
docstring: Returns True if the target node is a leaf.
  
          Returns
          -------
          leafness : bool
              True if the target node is a leaf node.
docstring_summary: Returns True if the target node is a leaf.
docstring_tokens: Returns True if the target node is a leaf .
function: def is_leaf(self):
          """
          Returns True if the target node is a leaf.
  
          Returns
          -------
          leafness : bool
              True if the target node is a leaf node.
  
          """
          return self.left is None
function_tokens: def is_leaf ( self ) : return self . left is None