def add_handler(log_handler_level, handler, formatter=None, log_filter=None):
handler.setLevel(log_handler_level)<EOL>if formatter is not None:<EOL><INDENT>handler.setFormatter(formatter)<EOL><DEDENT>if log_filter is not None:<EOL><INDENT>handler.addFilter(log_filter)<EOL><DEDENT>log.addHandler(handler)<EOL>
:param log_handler_level:   str of the level to set for the handler
:param handler:             logging.Handler handler to add
:param formatter:           logging.Formatter instance to use
:param log_filter:          logging.filter instance to add to handler
:return:                    None