Hacked on views a bit

- using `del` isn't really idiomatic
- used default values for calls to `request.Get.get` instead of try/except
- `not` is more idiomatic than checking length of 0
 - checking for the positive case and doing something is probably clearer than `pass`ing on a condition and doing something in an `else`
- `or`s short-circuit behavior is more efficient than unconditionally having to do the `if`, IIRC. It's also shorter

The end/start date trick may be too clever. Your original ifs may be clearer and I'd be glad to revert. I have a habit of preferring one-liners. If the number of parameters changes though, having a static dict to use for look up (instead of recreating it on each call could be a good idea.