nodes: 0, module; 1, function_definition; 2, function_name:clear; 3, parameters; 4, block; 5, identifier:self; 6, expression_statement; 7, expression_statement; 8, expression_statement; 9, expression_statement; 10, comment:"""Remove all elements from this set.
  
          >>> from ngram import NGram
          >>> n = NGram(['spam', 'eggs'])
          >>> sorted(list(n))
          ['eggs', 'spam']
          >>> n.clear()
          >>> list(n)
          []
          """; 11, call; 12, assignment; 13, assignment; 14, attribute; 15, argument_list; 16, attribute; 17, dictionary; 18, attribute; 19, dictionary; 20, call; 21, identifier:clear; 22, identifier:self; 23, identifier:_grams; 24, identifier:self; 25, identifier:length; 26, identifier:super; 27, argument_list; 28, identifier:NGram; 29, identifier:self
code: def clear(self):
          """Remove all elements from this set.
  
          >>> from ngram import NGram
          >>> n = NGram(['spam', 'eggs'])
          >>> sorted(list(n))
          ['eggs', 'spam']
          >>> n.clear()
          >>> list(n)
          []
          """
          super(NGram, self).clear()
          self._grams = {}
          self.length = {}