ValueError: notnull where clause not supported

[sentry-io]

Sentry Issue: EXPORT-TOOL-2-PROD-L0-ES

ValueError: notnull where clause not supported
(1 additional frame(s) were not displayed)
...
  File "tasks/task_runners.py", line 380, in run_task
    source_path = source.path()
  File "osm_export_tool/sources.py", line 132, in path
    filters = OsmiumTool.filters(self.mapping)
  File "osm_export_tool/sources.py", line 91, in filters
    parts = cls.parts(prefix)
  File "osm_export_tool/sources.py", line 71, in parts
    return _parts(expr)
  File "osm_export_tool/sources.py", line 65, in _parts
    raise ValueError('{0} where clause not supported'.format(op))

ValueError: notnull where clause not supported