How to use the ttkwidgets.color.functions.hexa_to_rgb function in ttkwidgets

def test_hexa_to_rgb(self):
        self.assertEqual(tkf.hexa_to_rgb("#FFFFFF"), (255, 255, 255))
        self.assertEqual(tkf.hexa_to_rgb("#FFFFFFFF"), (255, 255, 255, 255))
        self.assertRaises(ValueError, tkf.hexa_to_rgb, "#FFFFF")

def test_hexa_to_rgb(self):
        self.assertEqual(tkf.hexa_to_rgb("#FFFFFF"), (255, 255, 255))
        self.assertEqual(tkf.hexa_to_rgb("#FFFFFFFF"), (255, 255, 255, 255))
        self.assertRaises(ValueError, tkf.hexa_to_rgb, "#FFFFF")

self.title(title)
        self.transient(self.master)
        self.resizable(False, False)
        self.rowconfigure(1, weight=1)

        self.color = ""
        self.alpha_channel = bool(alpha)
        style = ttk.Style(self)
        style.map("palette.TFrame", relief=[('focus', 'sunken')],
                  bordercolor=[('focus', "#4D4D4D")])
        self.configure(background=style.lookup("TFrame", "background"))

        if isinstance(color, str):
            if re.match(r"^#[0-9A-F]{8}$", color.upper()):
                col = hexa_to_rgb(color)
                self._old_color = col[:3]
                if alpha:
                    self._old_alpha = col[3]
                    old_color = color
                else:
                    old_color = color[:7]
            elif re.match(r"^#[0-9A-F]{6}$", color.upper()):
                self._old_color = hexa_to_rgb(color)
                old_color = color
                if alpha:
                    self._old_alpha = 255
                    old_color += 'FF'
            else:
                col = self.winfo_rgb(color)
                self._old_color = tuple(round2(c * 255 / 65535) for c in col)
                args = self._old_color

self.square.pack()

        frame = ttk.Frame(self)
        frame.columnconfigure(1, weight=1)
        frame.rowconfigure(1, weight=1)

        # --- color preview: initial color and currently selected color side by side
        preview_frame = ttk.Frame(frame, relief="groove", borderwidth=2)
        preview_frame.grid(row=0, column=0, sticky="nw", pady=2)
        if alpha:
            self._transparent_bg = create_checkered_image(42, 32)
            transparent_bg_old = create_checkered_image(42, 32,
                                                        (100, 100, 100, 255),
                                                        (154, 154, 154, 255))
            prev_old = overlay(transparent_bg_old, hexa_to_rgb(old_color))
            prev = overlay(self._transparent_bg, hexa_to_rgb(old_color))
            self._im_old_color = ImageTk.PhotoImage(prev_old, master=self)
            self._im_color = ImageTk.PhotoImage(prev, master=self)
            old_color_prev = tk.Label(preview_frame, padx=0, pady=0,
                                      image=self._im_old_color,
                                      borderwidth=0, highlightthickness=0)
            self.color_preview = tk.Label(preview_frame, pady=0, padx=0,
                                          image=self._im_color,
                                          borderwidth=0, highlightthickness=0)
        else:
            old_color_prev = tk.Label(preview_frame, background=old_color[:7],
                                      width=5, highlightthickness=0, height=2,
                                      padx=0, pady=0)
            self.color_preview = tk.Label(preview_frame, width=5, height=2,
                                          pady=0, background=old_color[:7],
                                          padx=0, highlightthickness=0)
        old_color_prev.bind("<1>", self._reset_preview)

r, g, b = hexa_to_rgb(color)
            self.red.set(r)
            self.green.set(g)
            self.blue.set(b)
            h, s, v = rgb_to_hsv(r, g, b)
            self.hue.set(h)
            self.saturation.set(s)
            self.value.set(v)
            self.bar.set(h)
            self.square.set_hsv((h, s, v))
            if self.alpha_channel:
                a = self.alpha.get()
                self.hexa.insert('end', ("%2.2x" % a).upper())
                self.alphabar.set_color((r, g, b, a))
        elif self.alpha_channel and re.match(r"^#[0-9A-F]{8}$", color):
            r, g, b, a = hexa_to_rgb(color)
            self.red.set(r)
            self.green.set(g)
            self.blue.set(b)
            self.alpha.set(a)
            self.alphabar.set_color((r, g, b, a))
            h, s, v = rgb_to_hsv(r, g, b)
            self.hue.set(h)
            self.saturation.set(s)
            self.value.set(v)
            self.bar.set(h)
            self.square.set_hsv((h, s, v))
        else:
            self._update_color_rgb()
        self._update_preview()

def _update_preview(self):
        """Update color preview."""
        color = self.hexa.get()
        if self.alpha_channel:
            prev = overlay(self._transparent_bg, hexa_to_rgb(color))
            self._im_color = ImageTk.PhotoImage(prev, master=self)
            self.color_preview.configure(image=self._im_color)
        else:
            self.color_preview.configure(background=color)

style = ttk.Style(self)
        style.map("palette.TFrame", relief=[('focus', 'sunken')],
                  bordercolor=[('focus', "#4D4D4D")])
        self.configure(background=style.lookup("TFrame", "background"))

        if isinstance(color, str):
            if re.match(r"^#[0-9A-F]{8}$", color.upper()):
                col = hexa_to_rgb(color)
                self._old_color = col[:3]
                if alpha:
                    self._old_alpha = col[3]
                    old_color = color
                else:
                    old_color = color[:7]
            elif re.match(r"^#[0-9A-F]{6}$", color.upper()):
                self._old_color = hexa_to_rgb(color)
                old_color = color
                if alpha:
                    self._old_alpha = 255
                    old_color += 'FF'
            else:
                col = self.winfo_rgb(color)
                self._old_color = tuple(round2(c * 255 / 65535) for c in col)
                args = self._old_color
                if alpha:
                    self._old_alpha = 255
                    args = self._old_color + (255,)
                old_color = rgb_to_hexa(*args)
        else:
            self._old_color = color[:3]
            if alpha:
                if len(color) < 4: