diff --git a/mlair/data_handler/__init__.py b/mlair/data_handler/__init__.py
index 01d660031bbbdda08eba80044a08fcb034d8171b..495b6e7c8604a839a084a2b78a54563c13eb06e6 100644
--- a/mlair/data_handler/__init__.py
+++ b/mlair/data_handler/__init__.py
@@ -13,4 +13,4 @@ from .bootstraps import BootStraps
 from .iterator import KerasIterator, DataCollection
 from .default_data_handler import DefaultDataHandler
 from .abstract_data_handler import AbstractDataHandler
-from .data_preparation_neighbors import DataHandlerNeighbors
+from .data_handler_neighbors import DataHandlerNeighbors
diff --git a/mlair/data_handler/advanced_data_handler.py b/mlair/data_handler/advanced_data_handler.py
index c2d210bffdb598b23c025f60b903ddef84e4509d..f04748e82f11116b265796afba7f401c1cad9342 100644
--- a/mlair/data_handler/advanced_data_handler.py
+++ b/mlair/data_handler/advanced_data_handler.py
@@ -10,15 +10,18 @@ import datetime as dt
 
 from mlair.data_handler import AbstractDataHandler
 
-from typing import Union, List
+from typing import Union, List, Tuple, Dict
+import logging
+from functools import reduce
+from mlair.helpers.join import EmptyQueryResult
+from mlair.helpers import TimeTracking
 
 number = Union[float, int]
 num_or_list = Union[number, List[number]]
 
 
 def run_data_prep():
-
-    from .data_preparation_neighbors import DataHandlerNeighbors
+    from .data_handler_neighbors import DataHandlerNeighbors
     data = DummyDataHandler("main_class")
     data.get_X()
     data.get_Y()
@@ -33,8 +36,7 @@ def run_data_prep():
 
 
 def create_data_prep():
-
-    from .data_preparation_neighbors import DataHandlerNeighbors
+    from .data_handler_neighbors import DataHandlerNeighbors
     path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "testdata")
     station_type = None
     network = 'UBA'
@@ -98,7 +100,7 @@ class DummyDataHandler(AbstractDataHandler):
 
 
 if __name__ == "__main__":
-    from mlair.data_handler.station_preparation import DataHandlerSingleStation
+    from mlair.data_handler.data_handler_single_station import DataHandlerSingleStation
     from mlair.data_handler.iterator import KerasIterator, DataCollection
     data_prep = create_data_prep()
     data_collection = DataCollection(data_prep)
diff --git a/mlair/data_handler/data_preparation_neighbors.py b/mlair/data_handler/data_handler_neighbors.py
similarity index 100%
rename from mlair/data_handler/data_preparation_neighbors.py
rename to mlair/data_handler/data_handler_neighbors.py
diff --git a/mlair/data_handler/station_preparation.py b/mlair/data_handler/data_handler_single_station.py
similarity index 100%
rename from mlair/data_handler/station_preparation.py
rename to mlair/data_handler/data_handler_single_station.py
diff --git a/mlair/data_handler/default_data_handler.py b/mlair/data_handler/default_data_handler.py
index d8ec3c4fe18582280f499e598022d68254a0a7a9..8ed4f8743d90b313d074a3be15cc49fd9ffa07c0 100644
--- a/mlair/data_handler/default_data_handler.py
+++ b/mlair/data_handler/default_data_handler.py
@@ -16,7 +16,6 @@ import numpy as np
 import xarray as xr
 
 from mlair.data_handler.abstract_data_handler import AbstractDataHandler
-from mlair.data_handler.data_handler_single_station import DataHandlerSingleStation
 from mlair.helpers import remove_items, to_list
 from mlair.helpers.join import EmptyQueryResult
 
diff --git a/mlair/run_modules/pre_processing.py b/mlair/run_modules/pre_processing.py
index f074863ecf0e48bc0ebe23ae8f6e9fa657b6cd54..9b8ebbb2a88b879fe3549c2cba70fd8085d965fb 100644
--- a/mlair/run_modules/pre_processing.py
+++ b/mlair/run_modules/pre_processing.py
@@ -11,7 +11,7 @@ import numpy as np
 import pandas as pd
 
 from mlair.data_handler import DataCollection, AbstractDataHandler
-from mlair.helpers import TimeTracking, to_list
+from mlair.helpers import TimeTracking
 from mlair.configuration import path_config
 from mlair.helpers.join import EmptyQueryResult
 from mlair.run_modules.run_environment import RunEnvironment