Not able to send attachments in messages. "Attachment is not JSON serializable"

[markospacetech]

using the example

views = Views()
image = ImageView(original=Image(src=url, width=400, height=400),filename=filename)
views.image = image
attachment = Attachment(title="xxx", description="xxx", views=views)

res = chat.send_message(token="token url", to="channel name", text="xxx", attachments=[attachment])

gives the error

TypeError: Object of type Attachment is not JSON serializable