If you create a dataset containing a class with a name consisting of only one character (e.g. x) then an error is returned during validation:

Class name must be between 1 and 100 characters

the size of x is between 1 and 100, so either the check is wrong or the message is wrong.

I think that we should allow class names of 1 character. This should be updated in https://github.com/metabrainz/acousticbrainz-server/blob/09e0f3c716e28d62d5a8f46db1b69edf36ec5c65/utils/dataset_validator.py