docs: def set_connection(connection=defaults.sqlalchemy_connection_string_default):
      """Set the connection string for SQLAlchemy
  
      :param str connection: SQLAlchemy connection string
      """
      cfp = defaults.config_file_path
      config = RawConfigParser()
  
      if not os.path.exists(cfp):
          with open(cfp, 'w') as config_file:
              config['database'] = {'sqlalchemy_connection_string': connection}
              config.write(config_file)
              log.info('create configuration file %s', cfp)
      else:
          config.read(cfp)
          config.set('database', 'sqlalchemy_connection_string', connection)
          with open(cfp, 'w') as configfile:
              config.write(configfile)