ApiKey is invalid? and some doubts about syntax

Kiszuriwalilibori

Hi. I have a small app which uses rebrickable API, like this:

https://rebrickable.com/api/v3/lego/minifigs/?key=e007ad9e034751e1cf1bc9128813e890

What I want is to use create more sophisticated request. It seem that it must be done with brickset.

So I try to use it like this:

https://brickset.com/api/v3.asmx/getSets?apiKey=e007ad9e034759e1cf1bc9128813e890&userHash=string&params={'theme':'space','year':'1978,1979'}HTTP/1.1

The problems are as follows:

1. when I write as above without user hash, it requests user hash. Docs said that user hash is optional. So, is it optional or mandatory?

2. How can I get user hash(if mandatory?)

3. Is rebrickable apiKey invalid in brickset? I receive comment on invalid apiKey. Do I must get a new, specific to brickset, one?

4. Anyway, I would be gratefull for working examples of brickset requests, really, it is not simple syntax.

5 Alternatively - is there a way - without brickset but with rebrickable - to fetch all figs related to  - for example - Harry Potter? i have checked many syntax versions with q, query, and similar, but nothing works (that is why investigate brickset).