pub fn validate_batches<SubBatchIter, SubIter, Sub, Instrument>(
batches: SubBatchIter,
) -> Result<Vec<Vec<Subscription<ExchangeId, Instrument, SubKind>>>, DataError>where
SubBatchIter: IntoIterator<Item = SubIter>,
SubIter: IntoIterator<Item = Sub>,
Sub: Into<Subscription<ExchangeId, Instrument, SubKind>>,
Instrument: InstrumentData + Ord,