Hamilton Open Source

Hello,

I'm interested in using the *`parameterize_extract_columns`* decorator, or preferably *`parameterize_extract_fields`.* 

From my understanding, those are not yet available?

Will they be available in near future?

Thanks in advance for the answer!
And thank you for developing this great tool. I find it really clever.

image.png

(In case I'm wrong, and it is implemented already, but it's error on my side)

I'm getting this exception:
```    raise NotImplementedError(
NotImplementedError: Cannot get column type for [<class 'pandas.core.frame.DataFrame'>]. Registered types are {}```

When I try:
```@parameterize_extract_columns(
    ParameterizedExtract(
        ('height_image_1', 'width_image_1', 'channels_image_1'),
        {'image': source('image1')}
    )
)
def image_shape(image: np.ndarray) -&gt; pd.DataFrame:
    height, width, channels = image.shape[:3]
    return pd.concat([pd.Series(height), pd.Series(width), pd.Series(channels)], axis=1)```

I deduced that this functionality is not implemented, since registered types is empty.

These are both available. Somethings odd — your pd import is just standard?