structured search space errors

[dareid]

Please see the following gist: https://gist.github.com/dareid/af04ea51ced11747d989. It can be seen that the exploration of the search space is not correct:

• the arguments provided sometimes contain a key for '2' which is not a parameter, it is a potential value for parameter 'a'.
• the arguments provided sometimes contain an empty key.
• in the output it can be seen that it crashes due to a key error, this sometimes crashes for key '' and sometimes for key '2'.

[claesenm]

Thanks for reporting this issue along with a much-appreciated MWE :-). I will get to this ASAP.