Platformsh\Cli\Helper\ShellHelperInterface::resolveCommand PHP Method

    public function resolveCommand($command);

 /**
  * Get the full path to the Drush executable.
  *
  * @return string
  */
 public function getDrushExecutable()
 {
     if (getenv('PLATFORMSH_CLI_DRUSH')) {
         return getenv('PLATFORMSH_CLI_DRUSH');
     }
     return $this->shellHelper->resolveCommand('drush');
 }