code: def register(self, classes=[]):
          
          if not isinstance(classes, list):
              raise AttributeError("plugins must be a list, not %s." % type(classes))
  
          plugin_registered = []
  
          for plugin_class in classes:
              plugin_name = plugin_class.__name__
              self.register_class(plugin_class, plugin_name)
              self._log.debug("Plugin %s registered" % plugin_name)
              plugin_registered.append(plugin_name)
  
          self._log.info("Plugins registered: %s" % ", ".join(plugin_registered))
docs: Registers new plugins.
  
          The registration only creates a new entry for a plugin inside the _classes dictionary.
          It does not activate or even initialise the plugin.
  
          A plugin must be a class, which inherits directly or indirectly from GwBasePattern.
  
          :param classes: List of plugin classes
          :type classes: list