nameerror: name 'fileupload' is not defined
def _upload():
_upload_widget = fileupload.FileUploadWidget()
def _cb(change):
global file_contents
decoded = io.StringIO(change['owner'].data.decode('utf-8'))
filename = change['owner'].filename
print('Uploaded `{}` ({:.2f} kB)'.format(
filename, len(decoded.read()) / 2 **10))
file_contents = decoded.getvalue()
_upload_widget.observe(_cb, names='data')
display(_upload_widget)
_upload()