code: public function prefix($prefix = '', $namespace = '')
      {
          $namespace === '' && $namespace = (string) $this->namespace;
  
          $prefix && $prefix[0] !== '/' && $prefix = '/' . $prefix;
  
          $namespace = str_replace('\\\\', '\\', $namespace . '\\');
  
          $this->prefix = (string) $prefix;
  
          $this->namespace = ltrim($namespace, '\\');
  
          return $this;
      }
docs: Sets a prefix for the succeeding route endpoints.
  
  @param  string $prefix
  @param  string $namespace
  @return self