+<BLANKLINE>
+walking filesystem:
+walk callback on ([], root, {'K0': 0.0,...})
+walk callback on (['root'], K0, 0.0)
+walk callback on (['root'], K1, 0.0)
+walk callback on (['root'], K10, 0.0)
+...
+walk callback on (['root'], K9, 0.0)
+walk callback on (['root'], Packages, {'PolarGraphs': ...})
+walk callback on (['root', 'Packages'], PolarGraphs, {...})
+walk callback on (['root', 'Packages', 'PolarGraphs'], V_bottom, 232.0)
+...
+walk callback on (['root', 'Packages'], WMDataBase, {...})
+...
+walk callback on (['root'], radiusQ1, <WaveRecord ...>)