def __init__(self, assets_dir=None, requirements_file="requirements.yml"):
        self.assets_dir = assets_dir or Path(".") / "assets"
        self.requirements = GroupedRequirements()
        self.requirements.load(requirements_file)
        self.temp_dir = mkdtemp()
def EVT_MOTION(event):
  global _mpos
  if event.LeftIsDown():
    if _mpos:
      (x,y),(mx,my) = event.Position,_mpos
      rotangles[0] += y-my
      rotangles[1] += x-mx
      refresh()    
    _mpos = event.Position