getThemes: Returns a table of themes with number of sets and years active.
Description
Brickset API documentation is available here:
https://brickset.com/article/52664/api-version-3-documentation/
Usage
getThemes(key = getOption("brickset_key"), ...)
Value
a data.frame with the themes.
Arguments
key
the Brickset API key.
...
other parameters passed to getUserHash including
the Brickset username and password if they are not available from
getOption('brickset_username') and getOption('brickset_password').