我可以在使用ipywidgets FileUpload widg时定义文件上载操作吗

Question

我想用widgets.FileUpload创建一个事件，就像我用widgets.Button创建一个事件一样。有没有办法做这样的事

import ipywidgets as widgets

def do_something_with_file(fu):

    content = fu.data[0].decode('utf-8') 
    # doing something with the file content and get some string output
    return 'some string'

str_file_upload = widgets.FileUpload(accept='.txt', multiple=False)
str_file_upload.on_upload(do_something_with_file)