def create_volume(dataset_id, size):
Testing `Count` aggregate with `.values()`.  See #15305.
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/blockdevice.py/IBlockDeviceAPI.create_volume--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/contrib/gis/tests/relatedapp/tests.py/RelatedGeoModelTest.test13c_count