Here is how to set a min and max for locations with a constrain attribute. A much better system then using walls.
here is the code used ..
constrain attribute self.position.x to max((0+( self.Size.Height /2)),min((480-( self.Size.Width /2)), game.Mouse.Position.X ))
constrain attribute self.position.y to max((0+( self.Size.Height /2)),min((320-( self.Size.Height /2)), game.Mouse.Position.Y ))
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