Swift UIView transform animation never goes counterclockwise

Question

I'm working on a project in which I need to rotate a UIView either clockwise or counterclockwise. However, the view only rotates clockwise.

    var clockwise = false // This is a placeholder for testing
    var cgFloat : CGFloat!

    if clockwise {
        cgFloat = CGFloat(Double.pi)
    } else {
        cgFloat = -CGFloat(Double.pi)
    }

    print ("clockwise \(clockwise) \(cgFloat)")

    UIView.animate(withDuration: 2.0, animations: {
        self.myView.transform = self.myView.transform.rotated(by: cgFloat)
    })

The value of cgFloat is always negative, however the view only rotates clockwise.

The console prints this value, so the CGFloat is negative: clockwise false Optional(-3.14159265358979)