def get(self, word, default=nil):
		"""
		Retrieves output value associated with word.

		If there is no word returns default value,
		and if default is not given rises KeyError.
		"""

		node = self.__get_node(word)
		output = nil
		if node:
			output = node.output

		if output is nil:
			if default is nil:
				raise KeyError("no key '%s'" % word)
			else:
				return default
		else:
			return output
Retrieves output value associated with word.

		If there is no word returns default value,
		and if default is not given rises KeyError.