Called from the fit method, this method generated a horizontal bar plot.

        If y is none, then draws a simple horizontal bar chart.
        If y is not none, then draws a stacked horizontal bar chart for each nan count per
        target values.

def draw(self, X, y, **kwargs):
        """Called from the fit method, this method generated a horizontal bar plot.

        If y is none, then draws a simple horizontal bar chart.
        If y is not none, then draws a stacked horizontal bar chart for each nan count per
        target values.
        """
        nan_col_counts = self.get_nan_col_counts()

        # the x locations for the groups
        self.ind = np.arange(len(self.features_))

        if y is None:
            self.ax.barh(self.ind - self.width / 2, nan_col_counts, self.width,
                            color=self.color, label=None)
        else:
            self.draw_stacked_bar(nan_col_counts)