Can anyone please let me know how to extend existing drush command class.

I am writing a custom module which provides custom content entity and created a devel generate plugin similar to ContentDevelGenerate.

It is working as expected to generate dummy content from UI . I would like to create a drush command as well for the devel generator plugin. Similar to DevelGenerateCommands content method I would like to add additional method to generate my custom content entity.

My drush command class as follows :

<?php  namespace Drupalomdb_apiCommands;  use Drupaldevel_generateCommandsDevelGenerateCommands;  /**  * Class to create omdb api entity drush commands.  */ class OmdbApiEntityDevelGenerateCommands extends DevelGenerateCommands {    /**    * Create omdb api entity items by drush command.    *    * @command devel-generate:omdb-api    * @aliases dgen:omdb-api, devel-generate-omdb-api    * @pluginId omdb_api_entity_devel_generate    * @validate-module-enabled omdb_api    *    * @param int $num    *   Number of omdb api entity items to generate.    * @param array $options    *   Array of options as described below.    *    * @option kill Delete all omdb api entity items before generating new omdb api entity.    * @option feedback An integer representing interval for insertion rate logging.    * @option skip-fields A comma delimited list of fields to omit when generating random values.    * @option languages A comma-separated list of language codes    */   public function omdbApiEntities($num = 50, array $options = ['kill' => FALSE, 'feedback' => 1000]) {     $this->generate();   }    /**    * Wrapper for calling the plugin instance generate function.    */   public function generate() {     $instance = $this->getPluginInstance();     $instance->generate($this->getParameters());   }  } 

OmdbApiEntityDevelGenerateCommands If i paste this method directly in DevelGenerateCommands class, command is working as expected. So it seems I am missing something to extend the DevelGenerateCommands class.

# drush.services.yml services:   omdb_api.devel_generate_commands:     class: Drupalomdb_apiCommandsOmdbApiEntityDevelGenerateCommands     tags:       - { name: develgenerate.command }