code: def _get(self, field):
          
          opts = {'model': self.__proxy__,
                  'model_name': self.__name__,
                  'field': field}
          response = _turicreate.extensions._nearest_neighbors.get_value(opts)
          return response['value']
docs: Return the value of a given field. The list of all queryable fields is
          detailed below, and can be obtained with the
          :func:`~turicreate.nearest_neighbors.NearestNeighborsModel._list_fields`
          method.
  
          +-----------------------+----------------------------------------------+
          |      Field            | Description                                  |
          +=======================+==============================================+
          | distance              | Measure of dissimilarity between two points  |
          +-----------------------+----------------------------------------------+
          | features              | Feature column names                         |
          +-----------------------+----------------------------------------------+
          | unpacked_features     | Names of the individual features used        |
          +-----------------------+----------------------------------------------+
          | label                 | Label column names                           |
          +-----------------------+----------------------------------------------+
          | leaf_size             | Max size of leaf nodes (ball tree only)      |
          +-----------------------+----------------------------------------------+
          | method                | Method of organizing reference data          |
          +-----------------------+----------------------------------------------+
          | num_examples          | Number of reference data observations        |
          +-----------------------+----------------------------------------------+
          | num_features          | Number of features for distance computation  |
          +-----------------------+----------------------------------------------+
          | num_unpacked_features | Number of unpacked features                  |
          +-----------------------+----------------------------------------------+
          | num_variables         | Number of variables for distance computation |
          +-----------------------+----------------------------------------------+
          | training_time         | Time to create the reference structure       |
          +-----------------------+----------------------------------------------+
          | tree_depth            | Number of levels in the tree (ball tree only)|
          +-----------------------+----------------------------------------------+
  
          Parameters
          ----------
          field : string
              Name of the field to be retrieved.
  
          Returns
          -------
          out
              Value of the requested field.