By calling .otherwise() on an attribute instance it is now possible to specify what alternative attribute to consider in case the first one didn't work. It is possible to chain calls to .otherwise() the same way tou would do in jQuery. In case of empty results, None is returned. Added example that illustrates how to use this function.
Docs updated
Changed implementation to be more pythonic
Removed import left from tests
updated API to handle kwargs for attrCoalesce