def subtract(a, b):
    return wrap(a - b)
HStore expression.  Returns a subset of an hstore defined by
dataset/ETHPy150Open andrewf/pcap2har/pcap2har/tcp/seq.py/subtract--crossover with--dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/dialects/postgresql/hstore.py/HSTORE.comparator_factory.slice