date_range not defined error
http://pandas.pydata.org/pandas-docs/stable/10min.html
Setting

```
In [63]: s1 = pd.Series([1,2,3,4,5,6],index=date_range('20130102',periods=6))
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-63-bfe1d6561bb0> in <module>()
----> 1 s1 = pd.Series([1,2,3,4,5,6],index=date_range('20130102',periods=6))

NameError: name 'date_range' is not defined
```

Python - pandas newbie, any help kindly appreciated.
I assume i can't move on in the 10 min tutorial if i can't get pass this error.
