code: protected function extractStep( $definition )
      {
          if ( ( $position = strpos( $definition, '/' ) ) !== false )
          {
              return (int)substr( $definition, $position + 1 );
          }
          return false;
      }
docs: Extract the stepping defined by a given cron column
  
  @param mixed $definition Cron definition to use for stepping extraction
  @return bool false if the stepping does not exist. Otherwise the step is
  returned as an int