Figuring out what dependencies are needed

alex23 wuwei23 at
Thu Dec 12 06:48:42 CET 2013

On 11/12/2013 10:44 PM, sal at wrote:
> I'm a Python beginner.  I want to use it for stats work, so I downloaded Anaconda which has several of the popular libraries already packaged for Mac OS X.
> Now I'd like to use the backtesting package from zipline (, but while running the test script in iPython, I receive the following error:
> AssertionError                            Traceback (most recent call last)
> <ipython-input-6-f921351f78e2> in <module>()
> ----> 1 data = load_from_yahoo()
>        2 dma = DualMovingAverage()
>        3 results =
> 1)  I assume that I'm missing some packages that aren't included in Anaconda, but how do I know which ones to upload?

You're not missing a package, you're missing parameters. This is the 
signature for load_from_yahoo:

     def load_from_yahoo(indexes=None,

The first thing it does is call a helper function 
`_load_raw_yahoo_data`, which has this assertion:

     assert indexes is not None or stocks is not None, """

As you're passing no parameters into `load_from_yahoo`, both `indexes` 
and `stocks` default to None, so the assertion fails. Take a look at the 
examples in the zipline library to see what it is expecting.
> 2)  Often I'll just unzip a library file and put the main folder in the iPython folder, but I notice there's usually a file in the main library folder.  I've been ignoring this.  Should I be using it?
> Thanks

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