Wem smart outlet throwing error during startup

Home Assistant release (hass --version):
0.48.0
Python release (python3 --version):
Python 3.4.2
Component/platform:
Raspberry Pi B+

Description of problem:
Wemo config failing to load with below error. Tried with discovery as well as setting static ip, but in both cases it is failing to load with this error. It used work fine with older version but both 0.47 and 0.48 is having this issue for me.

2017-07-04 19:59:25 ERROR (MainThread) [homeassistant.setup] Error during setup of component wemo
Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/setup.py", line 190, in _async_setup_component
    component.setup, hass, processed_config)
  File "/usr/lib/python3.4/asyncio/futures.py", line 388, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.4/asyncio/tasks.py", line 286, in _wakeup
    value = future.result()
  File "/usr/lib/python3.4/asyncio/futures.py", line 277, in result
    raise self._exception
  File "/usr/lib/python3.4/concurrent/futures/thread.py", line 54, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/components/wemo.py", line 82, in setup
    devices = [(device.host, device) for device in pywemo.discover_devices()]
  File "/home/homeassistant/.homeassistant/deps/pywemo/discovery.py", line 28, in discover_devices
    device = device_from_description(entry.location, mac)
  File "/home/homeassistant/.homeassistant/deps/pywemo/discovery.py", line 40, in device_from_description
    return device_from_uuid_and_location(uuid, mac, description_url)
  File "/home/homeassistant/.homeassistant/deps/pywemo/discovery.py", line 45, in device_from_uuid_and_location
    if uuid.startswith('uuid:Socket'):
AttributeError: 'NoneType' object has no attribute 'startswith'
2017-07-04 19:59:25 INFO (MainThread) [homeassistant.core] Bus:Handling <Event call_service[L]: domain=persistent_notification, service_data=message=The following components and platforms could not be set up:
* [wemo](https://home-assistant.io/components/wemo/)
Please check your config, title=Invalid config, notification_id=invalid_config, service_call_id=3053467184-12, service=create>

Problem-relevant configuration.yaml entries and steps to reproduce:


wemo:
  static:
    - 192.168.1.21