for name, surface in surfaces.groupby("topics"):
    export_gaze_positions_on_surface(
        directory,
        name.replace("surfaces.", ""),
        surface.data
    )
Extracting BOSS_WEST_SCREEN data...
Traceback (most recent call last):

  File "<ipython-input-8-36026849b23b>", line 5, in <module>
    surface.data

  File "/data/DATA_ANALYSIS/BOSS_PREPROCESSING/EYE/batchExportPupilLabs/Batch_Export.py", line 85, in export_gaze_positions_on_surface
    surface = surface.transform(extract_export_data, surface_name=name)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/series.py", line 3915, in transform
    return super().transform(func, *args, **kwargs)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/generic.py", line 10812, in transform
    result = self.agg(func, *args, **kwargs)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/series.py", line 3905, in aggregate
    result = func(self, *args, **kwargs)

  File "/data/DATA_ANALYSIS/BOSS_PREPROCESSING/EYE/batchExportPupilLabs/Batch_Export.py", line 102, in extract_export_data
    gaze_datum["timestamp"],

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/series.py", line 1071, in __getitem__
    result = self.index.get_value(self, key)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/indexes/numeric.py", line 420, in get_value
    loc = self.get_loc(k)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/indexes/numeric.py", line 479, in get_loc
    return super().get_loc(key, method=method, tolerance=tolerance)

  File "/home/bullock/anaconda3/envs/myenv/lib/python3.7/site-packages/pandas/core/indexes/base.py", line 2897, in get_loc
    return self._engine.get_loc(key)

  File "pandas/_libs/index.pyx", line 107, in pandas._libs.index.IndexEngine.get_loc

  File "pandas/_libs/index.pyx", line 126, in pandas._libs.index.IndexEngine.get_loc

  File "pandas/_libs/index.pyx", line 141, in pandas._libs.index.IndexEngine._get_loc_duplicates

TypeError: Cannot cast array data from dtype('float64') to dtype('<U32') according to the rule 'safe'