Simplified testing connection type

        for conn in connections.all():

            # If using in-memory sqlite databases, pass the connections to

            # the server thread.

            if (conn.settings_dict['ENGINE'].rsplit('.', 1)[-1] in ('sqlite3', 'spatialite')

            if (conn.vendor == 'sqlite'

                and conn.settings_dict['NAME'] == ':memory:'):

                # Explicitly enable thread-shareability for this connection

                conn.allow_thread_sharing = True

        # Restore sqlite connections' non-sharability

        for conn in connections.all():

            if (conn.settings_dict['ENGINE'].rsplit('.', 1)[-1] in ('sqlite3', 'spatialite')

            if (conn.vendor == 'sqlite'

                and conn.settings_dict['NAME'] == ':memory:'):

                conn.allow_thread_sharing = False