Simon experiment

Hello,
I have been trying to design a simple simon task in psychopy. I took help from an online youtube video.
The link is:

Instead of using X and O, in my experiment I am trying to use red and blue square images. So, I made some changes in the code they wrote. I replaced X and O with red and blue square images. Probably I did some mistake in the syntax, that’s why there is an error showing that the for eg., blue_square.png is not defined.

Could you please check and point out the mistake and tell me the correct way to write it.
Here is the code.

if expInfo['counterbalance'] == '0':
    bindings = {'blue_square.png': 'm', 'red_square.png': 'z'}
    if thisTrial['condition'] == 'incongruent':
        if thisTrial['stim'] == 'blue_square.png':
            thisTrial['stim'] = thisTrial['stim']
            'red_square.png' = ''
            ans = 'm'
        elif thisTrial['stim'] == 'red_square.png':
            'blue_square.png'= ''
            'red_square.png' = thisTrial['stim']
            ans = 'z'
    elif thisTrial['condition'] == 'congruent':
        if thisTrial['stim'] == 'blue_square.png':
            'blue_square.png'= ''
            'red_square.png'= thisTrial['stim']
            ans = 'm'
        elif thisTrial['stim'] == 'red_square.png':
            'blue_square.png'= thisTrial['stim']
            'red_square.png' = ''
            ans = 'z'
elif expInfo['counterbalance'] == '1':
    bindings = {'red_square.png': 'm', 'blue_square.png': 'z'}
    if thisTrial['condition'] == 'incongruent':
        if thisTrial['stim'] == 'blue_square.png':
            'blue_square.png' = '' 
            'red_square.png' = thisTrial['stim']
            ans = 'z'
        elif thisTrial['stim'] == 'red_square.png':
            'blue_square.png' = thisTrial['stim']
            'red_square.png' = ''
            ans = 'm'
    elif thisTrial['condition'] == 'congruent':
        if thisTrial['stim'] == 'blue_square.png':
            'blue_square.png' = thisTrial['stim']
            'red_square.png' = ''
            ans = 'z'
        elif thisTrial['stim'] == 'red_square.png':
            'blue_square.png' = '' 
            'red_square.png' = thisTrial['stim']
            ans = 'm'

I hope you can help me.
Thank you

This doesn’t make sense to me since neither is a variable.

I’m going to guess that you have a stimulus component called red_square and that you are trying to update its image attribute. The way to do that is to use the correct attribute name, which is .image, and not to put that in quotes. e.g.

red_square.image = thisTrial['stim']

The docs for that attribute are below. You need to refer to the documentation rather than just guess at attribute names: