python - Explicitly close a OGR result object from a call to ExecuteSQL

How can I explicitly close/release the result of an ExecuteSQL statement when querying a Spatialite database with OGR via Python? I have a simple query to return the SRID of a dataset. This works as expected. However, subsequent calls to ds.ExecuteSQL fail with the error 'SQL logic error or missing database' unless I iterate all the way through the result rows.

For example:

ogr.UseExceptions()

# This query returns a single row
sql = 'select distinct srid(geometry) from foo'
result = ds.ExecuteSQL(sql)
row = result.next()

epsg = row.GetField(0)

# This call fails
ds.ExecuteSQL('drop table bar')

Completing the iteration avoids the error:

_ = [r for r in result]

This is fine for simple cases, but not very explicit. I've tried calling result.Dereference(), row=None; result=None but these do not help. What is it that I'm missing here?

UPDATE The exception is only raised when I enable ogr.UseExceptions(). Otherwise the error passes silently and the drop table statement has no affect.