code: func (c *Context) GetPostFormMap(key string) (map[string]string, bool) {
  	req := c.Request
  	if err := req.ParseMultipartForm(c.engine.MaxMultipartMemory); err != nil {
  		if err != http.ErrNotMultipart {
  			debugPrint("error on parse multipart form map: %v", err)
  		}
  	}
  	dicts, exist := c.get(req.PostForm, key)
  
  	if !exist && req.MultipartForm != nil && req.MultipartForm.File != nil {
  		dicts, exist = c.get(req.MultipartForm.Value, key)
  	}
  
  	return dicts, exist
  }
docs: // GetPostFormMap returns a map for a given form key, plus a boolean value
  // whether at least one value exists for the given key.