[fill_missing_daybefore] doesn't seem to work in for-loop

[cdemulde]

The fill_missing_daybefore function works separately, in a for-loop, but not in a for-loop where another filling function is applied. Example:
This works:

for data in Q_data:
    dataset.fill_missing_interpolation(data,50,[dt.datetime(2016,5,23),dt.datetime(2016,5,24)],clear=True)
for data in Q_data:
    dataset.fill_missing_daybefore(data,[dt.datetime(2016,5,1),dt.datetime(2016,6,1)],range_to_replace=[0,5],filtered_only=True,clear=False)

This doesn't:

for data in Q_data:
    dataset.fill_missing_interpolation(data,50,[dt.datetime(2016,5,23),dt.datetime(2016,5,24)],clear=True)
    dataset.fill_missing_daybefore(data,[dt.datetime(2016,5,1),dt.datetime(2016,6,1)],range_to_replace=[0,5],filtered_only=True,clear=False)

In the last example, no filling with the day before is done (fill_missing_interpolation does work properly).