How to use the agate.data_types.Number function in agate

def validate(self, table):
        column = table.columns[self._column_name]

        if not isinstance(column.data_type, Number):
            raise DataTypeError('Mean can only be applied to columns containing Number data.')

        has_nulls = HasNulls(self._column_name).run(table)

        if has_nulls:
            warn_null_calculation(self, column)

def validate(self, table):
        column = table.columns[self._column_name]

        if not isinstance(column.data_type, Number):
            raise DataTypeError('PercentileRank column must contain Number data.')

def get_computed_data_type(self, table):
        return Number()

def get_aggregate_data_type(self, table):
        return Number()

def validate(self, table):
        column = table.columns[self._column_name]

        if not isinstance(column.data_type, Number):
            raise DataTypeError('StDev can only be applied to columns containing Number data.')

        has_nulls = HasNulls(self._column_name).run(table)

        if has_nulls:
            warn_null_calculation(self, column)

def get_aggregate_data_type(self, table):
        return Number()

def get_aggregate_data_type(self, table):
        column = table.columns[self._column_name]

        if (isinstance(column.data_type, Number) or
        isinstance(column.data_type, Date) or
        isinstance(column.data_type, DateTime)):
            return column.data_type

def get_aggregate_data_type(self, table):
        return Number()

column_names = list(table.column_names[:max_columns])

    if columns_truncated:
        column_names.append(ELLIPSIS)

    widths = [len(n) for n in column_names]
    number_formatters = []
    formatted_data = []

    # Determine correct number of decimal places for each Number column
    for i, c in enumerate(table.columns):
        if i >= max_columns:
            break

        if isinstance(c.data_type, Number):
            max_places = max_precision(c[:max_rows])
            number_formatters.append(make_number_formatter(max_places))
        else:
            number_formatters.append(None)

    # Format data and display column widths
    for i, row in enumerate(table.rows):
        if i >= max_rows:
            break

        formatted_row = []

        for j, v in enumerate(row):
            if j >= max_columns:
                v = ELLIPSIS
            elif v is None:

:code:`120`.
    :param output:
        A file-like object to print to. Defaults to :code:`sys.stdout`.
    :param printable:
        If true, only printable characters will be outputed.
    """
    y_label = label_column_name
    label_column = self._columns[label_column_name]

    # if not isinstance(label_column.data_type, Text):
    #     raise ValueError('Only Text data is supported for bar chart labels.')

    x_label = value_column_name
    value_column = self._columns[value_column_name]

    if not isinstance(value_column.data_type, Number):
        raise DataTypeError('Only Number data is supported for bar chart values.')

    output = output
    width = width

    # Format numbers
    decimal_places = utils.max_precision(value_column)
    value_formatter = utils.make_number_formatter(decimal_places)

    formatted_labels = []

    for label in label_column:
        formatted_labels.append(six.text_type(label))

    formatted_values = []