SSB-44: missing import os

CAL/CalibrationCommon/lib/datacontainers/holography_dataset.py

 import logging
-import h5py
+import os
 
+import h5py
 from lofar.calibration.common.datacontainers.holography_observation import HolographyObservation
+
 from .holography_dataset_definitions import *
 from .holography_specification import HolographySpecification
 
@@ -207,7 +209,8 @@ class HolographyDataset():
                 # the geometrical distance are not really cutting it since RA
                 # and DEC are coordinates of a spherical coordinate system.
                 # But here the pseudo distance is good enough. 
-                pseudo_distance[frequency_string][beamlet_string] = abs(ra - source_ra) + abs(dec - source_dec)
+                pseudo_distance[frequency_string][beamlet_string] = abs(ra - source_ra) + abs(
+                    dec - source_dec)
 
         # OK.  Done with all the iteration business.  Now check if across all
         # _frequencies the same beamlet is the central one.  It is allowed that
@@ -227,7 +230,8 @@ class HolographyDataset():
                 # All is good.  Only one central beamlet.
                 central_beamlet[frequency_string] = keys[values.index(minimal_distance)]
             else:
-                text = "Found %d beamlets that have the same distance from the source position. Therefore a unique central beamlet does not exist." % (values.count(minimal_distance))
+                text = "Found %d beamlets that have the same distance from the source position. Therefore a unique central beamlet does not exist." % (
+                    values.count(minimal_distance))
                 logger.error(text)
                 raise ValueError(text)
 
@@ -237,7 +241,9 @@ class HolographyDataset():
         # the set will be 1.
         central_beamlet_set = set(central_beamlet.values())
         if len(central_beamlet_set) == 1:
-            logger.debug("All is good, unicorns everywhere, there is only one central beamlet \"%s\" for all _frequencies.", central_beamlet_set)
+            logger.debug(
+                "All is good, unicorns everywhere, there is only one central beamlet \"%s\" for all _frequencies.",
+                central_beamlet_set)
         else:
             logger.warning("Multiple central beamlets have been identified: ", central_beamlet)
         return central_beamlet
@@ -561,7 +567,6 @@ class HolographyDataset():
 
             result.frequencies = list(f[HDS_FREQUENCY])
 
-
             result.ra_dec = dict()
             for frequency in f["RA_DEC"].keys():
                 for beamlet in f["RA_DEC"][frequency].keys():