TypeError when running stock prices examples

[rahulporuri]

This error was discovered when running the examples/demo/financial/stock_prices.py example.

In order to reproduce, simply load the example and start zooming out. This was observed on python 3.6 with wx toolkit.

>python stock_prices.py
c:\users\rporuri\work\github\ets\enable\kiva\agg\plat_support.py:188: wxPyDeprecationWarning: Call to deprecated item. Use GetHandle instead.
  self.draw(window_dc.GetHDC(), x, y, width, height)
Exception occurred in traits notification handler for event object: TraitChangeEvent(object=<chaco.data_range_1d.DataRange1D object at 0x000001C06339C518>, name='updated', old=<undefined>, new=(1614674109.0105073, 1657874109.0105073))
Traceback (most recent call last):
  File "C:\Users\rporuri\.edm\envs\enable-test-3.6-wx\lib\site-packages\traits\observation\_trait_event_notifier.py", line 122, in __call__
    self.dispatcher(handler, event)
  File "C:\Users\rporuri\.edm\envs\enable-test-3.6-wx\lib\site-packages\traits\observation\observe.py", line 26, in dispatch_same
    handler(event)
  File "stock_prices.py", line 147, in _plot_range_handler
    low, high = event
TypeError: 'TraitChangeEvent' object is not iterable
Exception occurred in traits notification handler for event object: TraitChangeEvent(object=<chaco.data_range_1d.DataRange1D object at 0x000001C06339C518>, name='updated', old=<undefined>, new=(1593074109.0105073, 1679474109.0105073))
Traceback (most recent call last):
  File "C:\Users\rporuri\.edm\envs\enable-test-3.6-wx\lib\site-packages\traits\observation\_trait_event_notifier.py", line 122, in __call__
    self.dispatcher(handler, event)
  File "C:\Users\rporuri\.edm\envs\enable-test-3.6-wx\lib\site-packages\traits\observation\observe.py", line 26, in dispatch_same
    handler(event)
  File "stock_prices.py", line 147, in _plot_range_handler
    low, high = event
TypeError: 'TraitChangeEvent' object is not iterable