from System.Collections.Generic import *
import math
view = doc.GetElement(ElementId(206488))
viewer = view.GetDependentElements(ElementCategoryFilter(BuiltInCategory.OST_Viewers))[0]
coordinateSystem = view.CropBox.Transform
axis = Line.CreateUnbound(coordinateSystem.Origin, coordinateSystem.BasisY)
tx = Transaction(doc, "ss")
tx.Start()
ElementTransformUtils.RotateElement(doc, viewer, axis, math.pi)
tx.Commit()