Manage style and color based on column number and its label.
        Returns tuple of appropriate style and kwds which "color" may be added.

def _apply_style_colors(self, colors, kwds, col_num, label):
        """
        Manage style and color based on column number and its label.
        Returns tuple of appropriate style and kwds which "color" may be added.
        """
        style = None
        if self.style is not None:
            if isinstance(self.style, list):
                try:
                    style = self.style[col_num]
                except IndexError:
                    pass
            elif isinstance(self.style, dict):
                style = self.style.get(label, style)
            else:
                style = self.style

        has_color = 'color' in kwds or self.colormap is not None
        nocolor_style = style is None or re.match('[a-z]+', style) is None
        if (has_color or self.subplots) and nocolor_style:
            kwds['color'] = colors[col_num % len(colors)]
        return style, kwds