[Python] Pandas resample: when resampling from hours to quarterhours, the last three...

I am trying to resample an hourly pandas DataFrame to one with a quarterhourly index. It is left-labeled, so when the index says DD-mm-YYYY 10:00, it indicates the hour 10:00 to 11:00. However, if I do this, the last three quarterhours of the last hour are missing. Code example:

import datetime
import pandas as pd

start_date = datetime.datetime(2025, 5, 12, 10)
index = pd.date_range(start=start_date, periods=3, freq="h")

asd = pd.DataFrame(data=[1, 2, 3], index=index)

asd_qh = asd.resample("15min").ffill()
print(asd_qh)


The last rows are:

[..]
2025-05-12 11:30:00 2
2025-05-12 11:45:00 2
2025-05-12 12:00:00 3


but they should be:

[..]
2025-05-12 11:30:00 2
2025-05-12 11:45:00 2
2025-05-12 12:00:00 3
2025-05-12 12:15:00 3
2025-05-12 12:30:00 3
2025-05-12 12:45:00 3

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