Tests fail for Django 3

[SebCorbin]

Stack trace

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ERROR: test_intersectionpercentbyarea_valid (tests.test_terra.Test_TestTerra_LayerClusters)
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Traceback (most recent call last):
  File "/app/sample_project/tests/test_terra.py", line 149, in test_intersectionpercentbyarea_valid
    identifier=identifier, record=record))
  File "/app/terra_bonobo_nodes/terra.py", line 257, in __call__
    zone=Union('intersection')
  File "/app/venv/lib/python3.7/site-packages/django/db/models/query.py", line 384, in aggregate
    return query.get_aggregation(self.db, kwargs)
  File "/app/venv/lib/python3.7/site-packages/django/db/models/sql/query.py", line 507, in get_aggregation
    result = next(compiler.apply_converters((result,), converters))
  File "/app/venv/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1088, in apply_converters
    value = converter(value, expression, connection)
  File "/app/venv/lib/python3.7/site-packages/django/contrib/gis/db/backends/postgis/operations.py", line 385, in converter
    return None if value is None else GEOSGeometryBase(read(value), geom_class)
  File "/app/venv/lib/python3.7/site-packages/django/contrib/gis/geos/prototypes/io.py", line 153, in read
    return wkb_reader_read_hex(self.ptr, wkb, len(wkb))
  File "/app/venv/lib/python3.7/site-packages/django/contrib/gis/geos/libgeos.py", line 154, in __call__
    return self.func(*args, **kwargs)
  File "/app/venv/lib/python3.7/site-packages/django/contrib/gis/geos/prototypes/threadsafe.py", line 47, in __call__
    return self.cfunc(self.thread_context.handle.ptr, *args)
ctypes.ArgumentError: argument 3: <class 'TypeError'>: wrong type