Port a trained estimator to the syntax of a chosen programming language.

        Parameters
        ----------
        :param class_name : string
            The name of the class in the returned result.
        :param method_name : string
            The name of the method in the returned result.
        :param export_data : bool, default: False
            Whether the model data should be saved or not.
        :param export_dir : string, default: '.' (current directory)
            The directory where the model data should be saved.
        :param export_filename : string, default: 'data.json'
            The filename of the exported model data.
        :param export_append_checksum : bool, default: False
            Whether to append the checksum to the filename or not.

        Returns
        -------
        :return : string
            The transpiled algorithm with the defined placeholders.

def export(self, class_name, method_name, export_data=False,
               export_dir='.', export_filename='data.json',
               export_append_checksum=False, **kwargs):
        """
        Port a trained estimator to the syntax of a chosen programming language.

        Parameters
        ----------
        :param class_name : string
            The name of the class in the returned result.
        :param method_name : string
            The name of the method in the returned result.
        :param export_data : bool, default: False
            Whether the model data should be saved or not.
        :param export_dir : string, default: '.' (current directory)
            The directory where the model data should be saved.
        :param export_filename : string, default: 'data.json'
            The filename of the exported model data.
        :param export_append_checksum : bool, default: False
            Whether to append the checksum to the filename or not.

        Returns
        -------
        :return : string
            The transpiled algorithm with the defined placeholders.
        """
        # Arguments:
        self.class_name = class_name
        self.method_name = method_name

        # Estimator:
        est = self.estimator

        # Basic parameters:
        self.metric = est.metric
        self.n_classes = len(est.classes_)
        self.n_templates = len(est._fit_X)  # pylint: disable=W0212
        self.n_features = len(est._fit_X[0])  # pylint: disable=W0212
        self.n_neighbors = est.n_neighbors
        self.algorithm = est.algorithm
        self.power_param = est.p

        if self.algorithm != 'brute':
            from sklearn.neighbors.kd_tree import KDTree  # pylint: disable-msg=E0611
            from sklearn.neighbors.ball_tree import BallTree  # pylint: disable-msg=E0611
            tree = est._tree  # pylint: disable=W0212
            if isinstance(tree, (KDTree, BallTree)):
                self.tree = tree

        if self.target_method == 'predict':
            # Exported:
            if export_data and os.path.isdir(export_dir):
                self.export_data(export_dir, export_filename,
                                 export_append_checksum)
                return self.predict('exported')
            # Separated:
            return self.predict('separated')