我在 ubuntu 服务器上运行下面的测试代码。我正在尝试使用 zipline 回测一个简单的买入并持有策略。我只是想确保我已经正确安装了所有东西以进行回测。我对 zipline 很陌生。我收到以下错误，不知道为什么。
我正在按照此博客文章中的步骤进行操作：
https://towardsdatascience.com/introduction-to-backtesting-trading-strategies-7afae611a35e
我在 jupyter notebook 中运行代码。
当我之前运行代码以验证捆绑包已被摄取时，它显示的是：
代码：
!zipline bundles
输出：
apple-prices-2017-2019 2020-06-06 20:33:05.356288
apple-prices-2017-2019 2020-06-05 06:33:39.834841
apple-prices-2017-2019 2020-06-05 06:29:53.091904
apple-prices-2017-2019 2020-06-05 06:26:56.583051
csvdir <no ingestions>
quandl 2020-06-06 20:25:58.737940
quandl 2020-06-06 20:18:01.977412
quantopian-quandl 2020-06-04 16:15:57.717373
quantopian-quandl 2020-05-29 05:59:54.967114
下面是我在 jupyter notebook 中运行的代码以及错误。有没有人看到问题是什么，你能建议如何解决吗？
代码：
%%zipline --start 2016-1-1 --end 2017-12-31 --capital-base 1050.0 -o buy_and_hold.pkl
# imports
from zipline.api import order, symbol, record
# parameters
selected_stock = 'AAPL'
n_stocks_to_buy = 10
def initialize(context):
context.has_ordered = False
def handle_data(context, data):
# record price for further inspection
record(price=data.current(symbol(selected_stock), 'price'))
# trading logic
if not context.has_ordered:
# placing order, negative number for sale/short
order(symbol(selected_stock), n_stocks_to_buy)
# setting up a flag for holding a position
context.has_ordered = True
错误：
---------------------------------------------------------------------------
JSONDecodeError Traceback (most recent call last)
<ipython-input-10-d11030c42e8b> in <module>()
----> 1 get_ipython().run_cell_magic('zipline', '--start 2016-1-1 --end 2017-12-31 --capital-base 1050.0 -o buy_and_hold.pkl', "\n# imports\nfrom zipline.api import order, symbol, record\n\n# parameters\nselected_stock = 'AAPL'\nn_stocks_to_buy = 10\n\ndef initialize(context):\n context.has_ordered = False \n\ndef handle_data(context, data):\n # record price for further inspection\n record(price=data.current(symbol(selected_stock), 'price'))\n \n # trading logic\n if not context.has_ordered:\n # placing order, negative number for sale/short\n order(symbol(selected_stock), n_stocks_to_buy)\n # setting up a flag for holding a position\n context.has_ordered = True")
~/anaconda3/envs/py36/lib/python3.5/site-packages/IPython/core/interactiveshell.py in run_cell_magic(self, magic_name, line, cell)
2165 magic_arg_s = self.var_expand(line, stack_depth)
2166 with self.builtin_trap:
-> 2167 result = fn(magic_arg_s, cell)
2168 return result
2169
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/__main__.py in zipline_magic(line, cell)
309 '%s%%zipline' % ((cell or '') and '%'),
310 # don't use system exit and propogate errors to the caller
--> 311 standalone_mode=False,
312 )
313 except SystemExit as e:
~/anaconda3/envs/py36/lib/python3.5/site-packages/click/core.py in main(self, args, prog_name, complete_var, standalone_mode, **extra)
780 try:
781 with self.make_context(prog_name, args, **extra) as ctx:
--> 782 rv = self.invoke(ctx)
783 if not standalone_mode:
784 return rv
~/anaconda3/envs/py36/lib/python3.5/site-packages/click/core.py in invoke(self, ctx)
1064 _maybe_show_deprecated_notice(self)
1065 if self.callback is not None:
-> 1066 return ctx.invoke(self.callback, **ctx.params)
1067
1068
~/anaconda3/envs/py36/lib/python3.5/site-packages/click/core.py in invoke(*args, **kwargs)
608 with augment_usage_errors(self):
609 with ctx:
--> 610 return callback(*args, **kwargs)
611
612 def forward(*args, **kwargs): # noqa: B902
~/anaconda3/envs/py36/lib/python3.5/site-packages/click/decorators.py in new_func(*args, **kwargs)
19
20 def new_func(*args, **kwargs):
---> 21 return f(get_current_context(), *args, **kwargs)
22
23 return update_wrapper(new_func, f)
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/__main__.py in run(ctx, algofile, algotext, define, data_frequency, capital_base, bundle, bundle_timestamp, start, end, output, trading_calendar, print_algo, metrics_set, local_namespace, blotter)
274 local_namespace=local_namespace,
275 environ=os.environ,
--> 276 blotter=blotter,
277 )
278
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/utils/run_algo.py in _run(handle_data, initialize, before_trading_start, analyze, algofile, algotext, defines, data_frequency, capital_base, data, bundle, bundle_timestamp, start, end, output, trading_calendar, print_algo, metrics_set, local_namespace, environ, blotter)
157 trading_calendar=trading_calendar,
158 trading_day=trading_calendar.day,
--> 159 trading_days=trading_calendar.schedule[start:end].index,
160 )
161 first_trading_day =\
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/finance/trading.py in __init__(self, load, bm_symbol, exchange_tz, trading_calendar, trading_day, trading_days, asset_db_path, future_chain_predicates, environ)
101 trading_day,
102 trading_days,
--> 103 self.bm_symbol,
104 )
105
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/data/loader.py in load_market_data(trading_day, trading_days, bm_symbol, environ)
147 # date so that we can compute returns for the first date.
148 trading_day,
--> 149 environ,
150 )
151 tc = ensure_treasury_data(
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/data/loader.py in ensure_benchmark_data(symbol, first_date, last_date, now, trading_day, environ)
214
215 try:
--> 216 data = get_benchmark_returns(symbol)
217 data.to_csv(get_data_filepath(filename, environ))
218 except (OSError, IOError, HTTPError):
~/anaconda3/envs/py36/lib/python3.5/site-packages/zipline/data/benchmarks.py in get_benchmark_returns(symbol)
33 'https://api.iextrading.com/1.0/stock/{}/chart/5y'.format(symbol)
34 )
---> 35 data = r.json()
36
37 df = pd.DataFrame(data)
~/anaconda3/envs/py36/lib/python3.5/site-packages/requests/models.py in json(self, **kwargs)
894 # used.
895 pass
--> 896 return complexjson.loads(self.text, **kwargs)
897
898 @property
~/anaconda3/envs/py36/lib/python3.5/json/__init__.py in loads(s, encoding, cls, object_hook, parse_float, parse_int, parse_constant, object_pairs_hook, **kw)
317 parse_int is None and parse_float is None and
318 parse_constant is None and object_pairs_hook is None and not kw):
--> 319 return _default_decoder.decode(s)
320 if cls is None:
321 cls = JSONDecoder
~/anaconda3/envs/py36/lib/python3.5/json/decoder.py in decode(self, s, _w)
337
338 """
--> 339 obj, end = self.raw_decode(s, idx=_w(s, 0).end())
340 end = _w(s, end).end()
341 if end != len(s):
~/anaconda3/envs/py36/lib/python3.5/json/decoder.py in raw_decode(self, s, idx)
355 obj, end = self.scan_once(s, idx)
356 except StopIteration as err:
--> 357 raise JSONDecodeError("Expecting value", s, err.value) from None
358 return obj, end
JSONDecodeError: Expecting value: line 1 column 1 (char 0)