GetGenerator will find a generator matching args.Type if one was registered or return an error.

Creates a random float generator with exponential distribution where the minimal value is args.MinVal and the mean value is (args.MinVal+args.MaxVal)/2.

Creates a random float generator with a normal distribution with the mean equal to the mean of args.MinVal and args.MaxVal and with both MinVal and MaxVal one stDev away from the mean.

NewOneOfGenerator constructs a oneOfGenerator.

TODO: add length?.