code: def load_plugin(plugin_name):
      
      plugin_cls = plugin_map.get(plugin_name, None)
      if not plugin_cls:
          try:
              plugin_module_name, plugin_cls_name = plugin_name.split(":")
              plugin_module = import_module(plugin_module_name)
              plugin_cls = getattr(plugin_module, plugin_cls_name)
          except ValueError:
              raise click.ClickException(
                  '"{}" is not a valid plugin path'.format(plugin_name)
              )
          except ImportError:
              raise click.ClickException(
                  '"{}" does not name a Python module'.format(
                      plugin_module_name
                  )
              )
          except AttributeError:
              raise click.ClickException(
                  'Module "{}" does not contain the class "{}"'.format(
                      plugin_module_name, plugin_cls_name
                  )
              )
      return plugin_cls
docs: Given a plugin name, load plugin cls from plugin directory.
      Will throw an exception if no plugin can be found.