Show tooltip.

        Tooltips will disappear if mouse hovers them. They are meant for quick
        inspections.

def show_tooltip(self, title, text, color=_DEFAULT_TITLE_COLOR,
                     at_line=None, at_position=None, at_point=None):
        """
        Show tooltip.

        Tooltips will disappear if mouse hovers them. They are meant for quick
        inspections.
        """
        if text is not None and len(text) != 0:
            # Find position of calltip
            point = self._calculate_position(
                at_line=at_line,
                at_position=at_position,
                at_point=at_point,
            )

            # Format text
            tiptext = self._format_text(title, text, color, ellide=True)

            self._update_stylesheet(self.tooltip_widget)

            # Display tooltip
            self.tooltip_widget.show_tip(point, tiptext)
            self.tooltip_widget.show()