AttributeError: 'MultiScene' object has no attribute 'fixed_time_step'

[Predhead]

Hey there,

Ngl I thought this was pretty darn cool, so I tried to copy it across to my phone onto Pythonista. However, when I try to run I get the error listed in the title. I will attach visuals:

Not really sure I understand most of this, coding games isn’t something I’ve delved into before. Would really appreciate the help