code: def get_log_formats(config):
      
      # log_format name [params]
      log_format = Literal('log_format') + parameter + Group(OneOrMore(parameter)) + semicolon
      log_format.ignore(pythonStyleComment)
  
      for directive in log_format.searchString(config).asList():
          name = directive[1]
          format_string = ''.join(directive[2])
          yield name, format_string
docs: Parse config for log_format directives
      :return: iterator over ('format name', 'format string') tuple of found directives