

def iterrowgroupmap(source, key, mapper, header):
    (yield tuple(header))
    for (key, rows) in rowgroupby(source, key):
        for row in key(key, rows):
            (yield row)

dataset/ETHPy150Open alimanfoo/petl/petl/transform/maps.py iterrowgroupmap/VarMisuse@43/49 `mapper`->`key`