Unintuitive handling of seed in run.end()

[TheEimer]

Wen using the minimal recording example, I tried to add a "seed" to r.end(). Unfortunately, this argument is actually overwritten with None in some cases, spawning a very confusing assertion error of the seed being None when I definitely passed a different value. I don't know why the arguments are overwritten so I can't say if that makes sense or not, but the error should be handled differently in my opinion.