* Dataset is an iterable of DataEntry
* test_forecast_multivariate
* formatting
* offset can also be W-MON
* fix type
* fourier_time_features_from_frequency_str for weekly data
* randomly shuffle dataset for each worker
* filedataset is not scriptable
* read file randomly
* list and file datasets shuffle the time series in train
* do not shuffle time series in multivariate grouper
* fix tests
* formatting
* formatting