new h5py version doesn't support numerical event labels

[rgutzen]

It appears that with h5py version 3.0.0 there is some additional type control, and creating a neo.Event with numerical labels and saving it as .nix results in an error Can't implicitly convert non-string objects to strings (using neo 0.9.0, nixio 1.5.0b6, h5py 3.1.0). However, this was still possible when using h5py 2.10.0 and the same neo and nixio versions.
This may be the desired behavior as the neo documentation also says to use "(numpy.array 1D dtype=’U’ or list)" for event labels. Otherwise, for more flexibility, the nixio could try to convert labels itself and raise its own warnings or errors.

[jgrewe]

Hi @rgutzen, thanks for the report. I would prefer the more flexible approach. We will talk about it.

[achilleas-k]

Hey Robin. Like you said, Neo docs say labels should be unicode strings (dtype='U'), so if we do make this flexible, I would either do it in the Neo NIXIO as a convenience, or see if the Neo devs themselves would like to add the flexibility in the Event/Epoch constructor.