tailing constants part does not get flagged

Last value does not get flagged, although it should be:

import pandas as pd
from saqc import SaQC

data = pd.DataFrame({"a": [1,2,3,4,5,9,9,9,9,9]})

qc = SaQC(data=data, scheme="dmp")
qc = qc.flagConstants("a", thresh=1, window=3)
print(pd.merge(data, qc.flags['a'], left_index=True, right_index=True))

   a quality_flag quality_cause                           quality_comment
0  1          NIL
1  2          NIL
2  3          NIL
3  4          NIL
4  5          NIL
5  9          BAD         OTHER  {"test": "flagConstants", "comment": ""}
6  9          BAD         OTHER  {"test": "flagConstants", "comment": ""}
7  9          BAD         OTHER  {"test": "flagConstants", "comment": ""}
8  9          BAD         OTHER  {"test": "flagConstants", "comment": ""}
9  9          NIL

added BUG accepted labels

assigned to @luenensc

Error in flagConstants function body will always lead to the last min_periods - 1 periods (as assigned in flagConstants) of the data not get flagged.

mentioned in merge request !867 (merged)