Add `.validated_data` in tutorial part 1.

[lovelydinosaur]

We should add .validated_data here. Opening the issue as I've not had time to check what it would return, but wanted to make sure we track this...

serializer = SnippetSerializer(data=data)
serializer.is_valid()
# True
serializer.save()
# <Snippet: Snippet object>

[jpadilla]

>>> serializer = SnippetSerializer(data=data)
>>> serializer.is_valid()
True
>>> serializer.validated_data
OrderedDict([('title', ''), ('code', u'print "hello, world"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])
>>> serializer.save()
<Snippet: Snippet object>

[xordoquy]

the output will be slightly different with py2: it'll be a {} instead of OrderedDict()

[jpadilla]

@xordoquy weird, I just tried that with python2.7

[xordoquy]

a lot of things have changed with py3 ;)

[xordoquy]

@jpadilla try {'a': 1}.keys() in python3 ;)

[jpadilla]

I think you might have meant py3 in #2214 (comment)

[jpadilla]

@xordoquy actually ran it again with python3.4 and got the same output for serializer.validated_data

>>> serializer.validated_data
OrderedDict([('title', ''), ('code', 'print "hello, world"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])