docs: 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