def train(self, x = None, y = None, training_frame = None, fold_column = None, 
              weights_column = None, validation_frame = None, leaderboard_frame = None, blending_frame = None):
        """
        Begins an AutoML task, a background task that automatically builds a number of models
        with various algorithms and tracks their performance in a leaderboard. At any point 
        in the process you may use H2O's performance or prediction functions on the resulting 
        models.

        :param x: A list of column names or indices indicating the predictor columns.
        :param y: An index or a column name indicating the response column.
        :param fold_column: The name or index of the column in training_frame that holds per-row fold
            assignments.
        :param weights_column: The name or index of the column in training_frame that holds per-row weights.
        :param training_frame: The H2OFrame having the columns indicated by x and y (as well as any
            additional columns specified by fold_column or weights_column).
        :param validation_frame: H2OFrame with validation data. This argument is ignored unless the user sets 
            nfolds = 0. If cross-validation is turned off, then a validation frame can be specified and used 
            for early stopping of individual models and early stopping of the grid searches.  By default and 
            when nfolds > 1, cross-validation metrics will be used for early stopping and thus validation_frame will be ignored.
        :param leaderboard_frame: H2OFrame with test data for scoring the leaderboard.  This is optional and
            if this is set to None (the default), then cross-validation metrics will be used to generate the leaderboard 
            rankings instead.
        :param blending_frame: H2OFrame used to train the the metalearning algorithm in Stacked Ensembles (instead of relying on cross-validated predicted values).
            This is optional, but when provided, it is also recommended to disable cross validation 
            by setting `nfolds=0` and to provide a leaderboard frame for scoring purposes.

        :returns: An H2OAutoML object.

        :examples:
        >>> # Set up an H2OAutoML object
        >>> aml = H2OAutoML(max_runtime_secs=30)
        >>> # Launch an AutoML run
        >>> aml.train(y=y, training_frame=train)
        """
        ncols = training_frame.ncols
        names = training_frame.names

        #Set project name if None
        if self.project_name is None:
            self.project_name = "automl_" + training_frame.frame_id
            self.build_control["project_name"] = self.project_name

        # Minimal required arguments are training_frame and y (response)
        if y is None:
            raise ValueError('The response column (y) is not set; please set it to the name of the column that you are trying to predict in your data.')
        else:
            assert_is_type(y,int,str)
            if is_type(y, int):
                if not (-ncols <= y < ncols):
                    raise H2OValueError("Column %d does not exist in the training frame" % y)
                y = names[y]
            else:
                if y not in names:
                    raise H2OValueError("Column %s does not exist in the training frame" % y)
            input_spec = {
                'response_column': y,
            }

        if training_frame is None:
            raise ValueError('The training frame is not set!')
        else:
            assert_is_type(training_frame, H2OFrame)
            input_spec['training_frame'] = training_frame.frame_id

        if fold_column is not None:
            assert_is_type(fold_column,int,str)
            input_spec['fold_column'] = fold_column

        if weights_column is not None:
            assert_is_type(weights_column,int,str)
            input_spec['weights_column'] = weights_column

        if validation_frame is not None:
            assert_is_type(validation_frame, H2OFrame)
            input_spec['validation_frame'] = validation_frame.frame_id

        if leaderboard_frame is not None:
            assert_is_type(leaderboard_frame, H2OFrame)
            input_spec['leaderboard_frame'] = leaderboard_frame.frame_id

        if blending_frame is not None:
            assert_is_type(blending_frame, H2OFrame)
            input_spec['blending_frame'] = blending_frame.frame_id

        if self.sort_metric is not None:
            assert_is_type(self.sort_metric, str)
            sort_metric = self.sort_metric.lower()
            # Changed the API to use "deviance" to be consistent with stopping_metric values
            # TO DO: let's change the backend to use "deviance" since we use the term "deviance"
            # After that we can take this `if` statement out
            if sort_metric == "deviance":
                sort_metric = "mean_residual_deviance"
            input_spec['sort_metric'] = sort_metric

        if x is not None:
            assert_is_type(x,list)
            xset = set()
            if is_type(x, int, str): x = [x]
            for xi in x:
                if is_type(xi, int):
                    if not (-ncols <= xi < ncols):
                        raise H2OValueError("Column %d does not exist in the training frame" % xi)
                    xset.add(names[xi])
                else:
                    if xi not in names:
                        raise H2OValueError("Column %s not in the training frame" % xi)
                    xset.add(xi)
            x = list(xset)
            ignored_columns = set(names) - {y} - set(x)
            if fold_column is not None and fold_column in ignored_columns:
                ignored_columns.remove(fold_column)
            if weights_column is not None and weights_column in ignored_columns:
                ignored_columns.remove(weights_column)
            if ignored_columns is not None:
                input_spec['ignored_columns'] = list(ignored_columns)

        automl_build_params = dict(input_spec = input_spec)

        # NOTE: if the user hasn't specified some block of parameters don't send them!
        # This lets the back end use the defaults.
        automl_build_params['build_control'] = self.build_control
        automl_build_params['build_models']  = self.build_models

        resp = h2o.api('POST /99/AutoMLBuilder', json=automl_build_params)
        if 'job' not in resp:
            print("Exception from the back end: ")
            print(resp)
            return

        self._job = H2OJob(resp['job'], "AutoML")
        self._job.poll()
        self._fetch()
Begins an AutoML task, a background task that automatically builds a number of models
        with various algorithms and tracks their performance in a leaderboard. At any point 
        in the process you may use H2O's performance or prediction functions on the resulting 
        models.

        :param x: A list of column names or indices indicating the predictor columns.
        :param y: An index or a column name indicating the response column.
        :param fold_column: The name or index of the column in training_frame that holds per-row fold
            assignments.
        :param weights_column: The name or index of the column in training_frame that holds per-row weights.
        :param training_frame: The H2OFrame having the columns indicated by x and y (as well as any
            additional columns specified by fold_column or weights_column).
        :param validation_frame: H2OFrame with validation data. This argument is ignored unless the user sets 
            nfolds = 0. If cross-validation is turned off, then a validation frame can be specified and used 
            for early stopping of individual models and early stopping of the grid searches.  By default and 
            when nfolds > 1, cross-validation metrics will be used for early stopping and thus validation_frame will be ignored.
        :param leaderboard_frame: H2OFrame with test data for scoring the leaderboard.  This is optional and
            if this is set to None (the default), then cross-validation metrics will be used to generate the leaderboard 
            rankings instead.
        :param blending_frame: H2OFrame used to train the the metalearning algorithm in Stacked Ensembles (instead of relying on cross-validated predicted values).
            This is optional, but when provided, it is also recommended to disable cross validation 
            by setting `nfolds=0` and to provide a leaderboard frame for scoring purposes.

        :returns: An H2OAutoML object.

        :examples:
        >>> # Set up an H2OAutoML object
        >>> aml = H2OAutoML(max_runtime_secs=30)
        >>> # Launch an AutoML run
        >>> aml.train(y=y, training_frame=train)