Load configuration section from other configuration. If specified section doesn't exist in current
		configuration, then it will be added automatically.

		:param config: source configuration
		:param section_to: destination section name
		:param section_from: source section name (if it is None, then section_to is used as source section name)
		:return: None

def merge_section(self, config, section_to, section_from=None):
		""" Load configuration section from other configuration. If specified section doesn't exist in current
		configuration, then it will be added automatically.

		:param config: source configuration
		:param section_to: destination section name
		:param section_from: source section name (if it is None, then section_to is used as source section name)
		:return: None
		"""
		section_from = section_from if section_from is not None else section_to
		if section_from not in config.sections():
			raise ValueError('There is no such section "%s" in config' % section_from)

		if section_to not in self.sections():
			self.add_section(section_to)

		for option in config[section_from].keys():
			self.set(section_to, option, config[section_from][option])