Problem

There seems to be a problem with crossborder flows query_crossborder_flows. In particular, querying over DE -> NL crossborder flows over summer 2021, there is a bug in august. I assume it happens because the frequency in July is hourly data, and in September its quarterly (15min) data. Probably somewhere in august it switches from hourly to quarterly, which in turn messes up the dataframe and causes the error

Information

pandas: 1.3.4
entsoe-py: 0.4.1
python: 3.9.7
os: macOS monterey 12.0.1

Reproduction

July 2021: Correct

start = pd.Timestamp(str(int(2021_07_01)), tz='Europe/Amsterdam')
end = pd.Timestamp(str(int(2021_08_01)), tz='Europe/Amsterdam')
client.query_crossborder_flows("DE", "NL", start=start, end=end)

returns the expected output:

2021-07-01 00:00:00+02:00    1110.0
2021-07-01 01:00:00+02:00     925.0
2021-07-01 02:00:00+02:00     540.0
2021-07-01 03:00:00+02:00     743.0
2021-07-01 04:00:00+02:00     538.0
                              ...  
2021-07-31 19:00:00+02:00    1437.0
2021-07-31 20:00:00+02:00    1266.0
2021-07-31 21:00:00+02:00    2218.0
2021-07-31 22:00:00+02:00    2171.0
2021-07-31 23:00:00+02:00    2313.0
Freq: 60T, Length: 744, dtype: float64

September 2021: Correct

Similarly,

start = pd.Timestamp(str(int(2021_09_01)), tz='Europe/Amsterdam')
end = pd.Timestamp(str(int(2021_10_01)), tz='Europe/Amsterdam')
client.query_crossborder_flows("DE", "NL", start=start, end=end)

returns the expected output:

2021-09-01 00:00:00+02:00    2579.0
2021-09-01 00:15:00+02:00    2430.0
2021-09-01 00:30:00+02:00    2378.0
2021-09-01 00:45:00+02:00    2281.0
2021-09-01 01:00:00+02:00    2287.0
                              ...  
2021-09-30 22:45:00+02:00     843.0
2021-09-30 23:00:00+02:00    1210.0
2021-09-30 23:15:00+02:00    1191.0
2021-09-30 23:30:00+02:00    1233.0
2021-09-30 23:45:00+02:00    1233.0
Freq: 15T, Length: 2880, dtype: float64

August 2021: Problem

However this one fails:

start = pd.Timestamp(str(int(2021_08_01)), tz='Europe/Amsterdam')
end = pd.Timestamp(str(int(2021_09_01)), tz='Europe/Amsterdam')
client.query_crossborder_flows("DE", "NL", start=start, end=end)

with

ValueError: Length mismatch: Expected axis has 22 elements, new values have 85 elements

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Lastly, I just wanted to thank all contributors of this library, it has saved me enormous amount of time and headaches I had working with the entsoe XML API. Thanks!