It looks like the classes `MedianViewSet`, `MeanViewSet`, `ModeViewSet`, and `RangeViewSet`, should be combined into a single class to reduce code duplication.  This can take a `statistic_type` or similar parameter that is passed as e.g. `median` and concatenated to get `"%s-list" % statistic_type` for the reverse parameter and maybe uses a dict
```python
{
    'median': get_median_for_numeric_fields_in_form,
    ...,
}[statistic_type]
```
to set the data.