@classmethod
def RegisterPlugins(cls, plugin_classes):
    """Registers plugin classes.

    The plugin classes are identified based on their lower case name.

    Args:
      plugin_classes (list[type]): a list of class objects of the plugins.

    Raises:
      KeyError: if plugin class is already set for the corresponding name.
    """
    for plugin_class in plugin_classes:
        cls.RegisterPlugin(plugin_class)
