can't use > filter in list_datasets

[amueller]

trafficstars

import openml

# string or int doesn't matter
datasets = openml.datasets.list_datasets(number_classes="2")
len(datasets)

652

datasets = openml.datasets.list_datasets(number_classes=">1")
len(datasets)

0

[janvanrijn]

This is an issue for the OpenML rest API.