Remove mutable in signature and pop todo

this is not py2 anymore

game/scripts/interface/color_picker.rpy

@@ -12,14 +12,14 @@ screen color_picker(color, alpha, title, pos_xy, color_default):
     default hue = 0
     default sat = 0
     default val = 0
-    default _alpha = 0 # Avoid name conflict with 'alpha' screen variable in other active screens
+    default alpha_ = 0 # Avoid name conflict with 'alpha' screen variable in other active screens
     default edit_mode = False
     default preview_old = Solid(rgba)
     $ preview_new = Solid(rgba)
     $ gradient_map = SVGradientButton(
         color_picker_clicked,
         Fixed(
-            Color( tuple( x * 255 for x in colorsys.hsv_to_rgb(1 - hue, 1, 1) ) ),
+            Color(hsv=(1-hue, 1, 1)),
             Frame("interface/color_picker/saturation_value_gradient.webp")
         ),
         xysize=(255, 255),
@@ -213,7 +213,7 @@ screen color_picker(color, alpha, title, pos_xy, color_default):
                                 Transform(alpha_gradient_image, matrixcolor=ColorizeMatrix(rgba, rgba)))
                     bar:
                         xysize (255, 30)
-                        value ScreenVariableValue("_alpha", range=1.0, action=Function(color_picker_update_rgba))
+                        value ScreenVariableValue("alpha_", range=1.0, action=Function(color_picker_update_rgba))
                         base_bar icon_frame
                         thumb Image(gui.format("interface/color_picker/{}/cursor_v.webp"), xalign=0.5)
                         thumb_offset 0
@@ -234,11 +234,9 @@ define hue_gradient_image = HueSlider()
 
 init -1 python:
 
-    def color_picker(color=[0,0,0,0], alpha=True, title="Pick a colour", pos_xy=(240, 130), color_default=None):
-        # TODO: Remove external dependencies and utilise built-in Color class instead.
-
+    def color_picker(color=(0,0,0,0), alpha=True, title="Pick a colour", pos_xy=(240, 130), color_default=None):
         global picking_color
-        picking_color = color # Color object (list) to be updated live
+        picking_color = list(color) # Color object (list) to be updated live
         start_color = list(color) # Keep a copy
 
         renpy.show_screen("color_picker", tuple(color), alpha, title, pos_xy, color_default)
@@ -305,19 +303,19 @@ init -1 python:
     def color_picker_update_hsva():
         scope = renpy.get_screen("color_picker").scope
         (r, g, b, a) = scope["rgba"]
-        (h, s, v) = colorsys.rgb_to_hsv(r / 255.0, g / 255.0, b / 255.0)
+        (h, s, v) = Color((r, g, b)).hsv
         scope["hue"] = 1 - h
         scope["sat"] = s
         scope["val"] = v
-        scope["_alpha"] = a / 255.0
+        scope["alpha_"] = a / 255.0
 
     def color_picker_update_rgba():
         scope = renpy.get_screen("color_picker").scope
-        (r, g, b) = colorsys.hsv_to_rgb(1 - scope["hue"], scope["sat"], scope["val"])
+        (r, g, b) = Color(hsv=(1 - scope["hue"], scope["sat"], scope["val"])).rgb
         r = int(r * 255)
         g = int(g * 255)
         b = int(b * 255)
-        a = int(scope["_alpha"] * 255)
+        a = int(scope["alpha_"] * 255)
         scope["rgba"] = (r, g, b, a)
         update_picking_color(scope["rgba"])
         renpy.restart_interaction()
@@ -428,9 +426,7 @@ init -1 python:
     class SVGradientButton(ImageButton):
 
         def __init__(self, on_click, idle_image, *args, **kwargs):
-            kwargs['sensitive'] = True
-            kwargs['action'] = NullAction()
-            super(SVGradientButton, self).__init__(idle_image, *args, **kwargs)
+            super(SVGradientButton, self).__init__(idle_image, *args, sensitive=True, action=NullAction(), **kwargs)
             self.width = 0
             self.height = 0
             self.on_click = on_click

game/scripts/interface/credits.rpy

@@ -61,7 +61,7 @@ label credits:
     if not _menu:
         play music "music/Only 115 (Electro Loop)_125 BPM.ogg" fadein 1 fadeout 1 if_changed
 
-    $ renpy.scene("screens")
+    scene onlayer screens
 
     show screen credits(credits_text)
     with dissolve

game/scripts/utility/common_functions.rpy

@@ -5,7 +5,6 @@ init python early:
     import math
     import random
     import pygame
-    import colorsys
     import fnmatch
     import posixpath
     import re