imageView won't appear

[smath]

I'm working on an app using the ui library, and have run into a problem. Given input from the user, I will produce a plot with matplotlib, which I then plan to have appear in an imageView. The problem is that nothing happens when I press the button that's supposed to make the plot appear. Below is my code:

import ui

view = ui.View()
view.height = 800
view.width = 500					
view.name = 'Plot test'								
view.background_color = 'white'

def plot_button():
	img = ui.Image.named('plot.png')
	im = ui.ImageView()
	im.center = (view.width * 0.5, view.height*0.5)
	im.height = 350
	im.width = 500
	im.border_width = 2
	im.flex = 'LRTB'
	im.image = img
	view.add_subview(im)
	
go = ui.Button(title = 'Plot')
go.action = plot_button
go.width = 100
go.border_width = 1
go.border_color = 'grey'
go.center = (view.width/8, 20)
go.flex = 'LRTB'
view.add_subview(go)

view.present('fullscreen')	

[robinsiebler112]

It should be

def plot_button(sender):

[smath]

Perfect. Thanks.