def has_option(self, option_name):
		"""
		Check that an option exists.

		:param str option_name: The name of the option to check.
		:return: True of the option exists in the configuration.
		:rtype: bool
		"""
		if self.prefix:
			option_name = self.prefix + self.seperator + option_name
		item_names = option_name.split(self.seperator)
		node = self._storage
		for item_name in item_names:
			if node is None:
				return False
			if not item_name in node:
				return False
			node = node[item_name]
		return True
Check that an option exists.

		:param str option_name: The name of the option to check.
		:return: True of the option exists in the configuration.
		:rtype: bool