How to use the arctic.store.audit.ArcticTransaction function in arctic

def winning_writer():
        #will attempt to write version 2 as well
        with ArcticTransaction(library, 'FOO', 'user', 'log') as cwb:
            cwb.write('FOO', ts2, metadata={'foo': 'bar'})
            e2.wait()

def losing_writer():
        #will attempt to write version 2, should find that version 2 is there and it ends up writing version 3
        with pytest.raises(ConcurrentModificationException):
            with ArcticTransaction(library, 'FOO', 'user', 'log') as cwb:
                cwb.write('FOO', ts1_append, metadata={'foo': 'bar'})
                e1.wait()

def test_ArticTransaction_no_audit():
    vs = Mock(spec=VersionStore)
    ts1 = pd.DataFrame(index=[1, 2], data={'a':[1.0, 2.0]})
    vs.read.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=1, metadata=None, data=ts1)
    vs.write.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=2,
                            metadata=None, data=None)
    vs.list_versions.return_value = [{'version': 2}, {'version': 1}]

    with ArcticTransaction(vs, sentinel.symbol, sentinel.user, sentinel.log, audit=False) as cwb:
        cwb.write(sentinel.symbol, pd.DataFrame(index=[3, 4], data={'a': [1.0, 2.0]}), metadata=sentinel.meta)

    assert vs.write.call_count == 1
    assert vs._write_audit.call_count == 0

def test_metadata_changes_writes(library):
    with ArcticTransaction(library, symbol, 'u1', 'l1') as mt:
        mt.write(symbol, ts1, metadata={'original': 'data'})

    with ArcticTransaction(library, symbol, 'u2', 'l2') as mt:
        mt.write(symbol, ts1, metadata={'some': 'data', 'original': 'data'})

    audit_log = library.read_audit_log(symbol)
    assert audit_log == [{u'new_v': 2, u'symbol': u'TS1', u'message': u'l2', u'user': u'u2', u'orig_v': 1},
                         {u'new_v': 1, u'symbol': u'TS1', u'message': u'l1', u'user': u'u1', u'orig_v': 0}]
    assert_frame_equal(ts1, library.read(symbol, audit_log[0]['orig_v']).data)
    assert_frame_equal(ts1, library.read(symbol, audit_log[0]['new_v']).data)

    assert library.read(symbol, audit_log[0]['orig_v']).metadata == {'original': 'data'}
    assert library.read(symbol, audit_log[0]['new_v']).metadata == {'some': 'data', 'original': 'data'}

def test_audit_read(library):
    with ArcticTransaction(library, symbol3, 'u3', 'foo') as mt:
        mt.write(symbol3, ts1)

    with ArcticTransaction(library, symbol, 'u1', 'l1') as mt:
        mt.write(symbol, ts1)

    with ArcticTransaction(library, symbol, 'u2', 'l2') as mt:
        mt.write(symbol, ts2)

    with ArcticTransaction(library, symbol2, 'u2', 'l2') as mt:
        mt.write(symbol2, ts2)
        
    audit_log = library.read_audit_log()

    assert audit_log == [{u'new_v': 1, u'symbol': u'TS2', u'message': u'l2', u'user': u'u2', u'orig_v': 0},
                         {u'new_v': 2, u'symbol': u'TS1', u'message': u'l2', u'user': u'u2', u'orig_v': 1},
                         {u'new_v': 1, u'symbol': u'TS1', u'message': u'l1', u'user': u'u1', u'orig_v': 0},
                         {u'new_v': 1, u'symbol': u'TS3', u'message': u'foo', u'user': u'u3', u'orig_v': 0},
                         ]

    l2_audit_log = library.read_audit_log(message='l2')

    assert l2_audit_log == [{u'new_v': 1, u'symbol': u'TS2', u'message': u'l2', u'user': u'u2', u'orig_v': 0},

def test_ArcticTransaction_write_doesnt_skip_for_close_ts(library):
    orig_ts = read_str_as_pandas("""times |    PX_LAST
                  2014-10-31 21:30:00.000 | 204324.674
                  2014-11-13 21:30:00.000 |  193964.45
                  2014-11-14 21:30:00.000 | 193650.403""")

    with ArcticTransaction(library, symbol, 'u1', 'l1') as mt:
        mt.write(symbol, orig_ts)

    assert_frame_equal(library.read(symbol).data, orig_ts)

    # try and store slighty different TimeSeries
    new_ts = read_str_as_pandas("""times |    PX_LAST
                 2014-10-31 21:30:00.000 | 204324.672
                 2014-11-13 21:30:00.000 | 193964.453
                 2014-11-14 21:30:00.000 | 193650.406""")

    with ArcticTransaction(library, symbol, 'u1', 'l2') as mt:
        mt.write(symbol, new_ts)

    assert_frame_equal(library.read(symbol).data, new_ts)

def test_ArcticTransaction_writes_no_data_found():
    vs = Mock(spec=VersionStore)
    ts1 = pd.DataFrame(index=[1, 2], data={'a':[1.0, 2.0]})
    vs.read.side_effect = NoDataFoundException('no data')
    vs.write.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=1,
                            metadata=None, data=None)
    vs.list_versions.side_effect = [[],
                                   [{'version': 1}],
                                   ]

    with ArcticTransaction(vs, sentinel.symbol, sentinel.user, sentinel.log) as cwb:
        cwb.write(sentinel.symbol, ts1, metadata={1: 2})

    assert vs.write.call_args_list == [call(sentinel.symbol, ANY, prune_previous_version=True, metadata={1: 2})]
    assert vs.list_versions.call_args_list == [call(sentinel.symbol, latest_only=True),
                                              call(sentinel.symbol)]

def test_ArcticTransaction_writes_no_data_found_deleted():
    vs = Mock(spec=VersionStore)
    ts1 = pd.DataFrame(index=[1, 2], data={'a':[1.0, 2.0]})
    vs.read.side_effect = NoDataFoundException('no data')
    vs.write.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=3,
                            metadata=None, data=None)
    vs.list_versions.side_effect = [[{'version': 2}, {'version': 1}],
                                   [{'version': 3}, {'version': 2}],
                                   ]

    with ArcticTransaction(vs, sentinel.symbol, sentinel.user, sentinel.log) as cwb:
        cwb.write(sentinel.symbol, ts1, metadata={1: 2})

    assert vs.write.call_args_list == [call(sentinel.symbol, ANY, prune_previous_version=True, metadata={1: 2})]
    assert vs.list_versions.call_args_list == [call(sentinel.symbol, latest_only=True),
                                              call(sentinel.symbol)]

def test_ArcticTransaction_simple():
    vs = Mock(spec=VersionStore)
    ts1 = pd.DataFrame(index=[1, 2], data={'a':[1.0, 2.0]})
    vs.read.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=1, metadata=None, data=ts1)
    vs.write.return_value = VersionedItem(symbol=sentinel.symbol, library=sentinel.library, version=2,
                            metadata=None, data=None)
    vs.list_versions.return_value = [{'version': 2}, {'version': 1}]

    with ArcticTransaction(vs, sentinel.symbol, sentinel.user, sentinel.log) as cwb:
        cwb.write(sentinel.symbol, pd.DataFrame(index=[3, 4], data={'a': [1.0, 2.0]}), metadata=sentinel.meta)

    assert not vs._delete_version.called
    assert vs.write.call_args_list == [call(sentinel.symbol, ANY, prune_previous_version=True, metadata=sentinel.meta)]
    assert vs.list_versions.call_args_list == [call(sentinel.symbol)]
    assert vs._write_audit.call_args_list == [call(sentinel.user, sentinel.log, ANY)]

def _copy_symbol(symbols):
        for symbol in symbols:
            with ArcticTransaction(dest, symbol, USER, log) as mt:
                existing_data = dest.has_symbol(symbol)
                if existing_data:
                    if force:
                        logger.warn("Symbol: %s already exists in destination, OVERWRITING" % symbol)
                    elif splice:
                        logger.warn("Symbol: %s already exists in destination, splicing in new data" % symbol)
                    else:
                        logger.warn("Symbol: {} already exists in {}@{}, use --force to overwrite or --splice to join "
                                    "with existing data".format(symbol, _get_host(dest).get('l'),
                                                                _get_host(dest).get('mhost')))
                        continue

                version = src.read(symbol)
                new_data = version.data

                if existing_data and splice: