diff --git a/manim_slides/commons.py b/manim_slides/commons.py
index 83cacec..194721a 100644
--- a/manim_slides/commons.py
+++ b/manim_slides/commons.py
@@ -1,9 +1,12 @@
+from typing import Callable
+
 import click
 
 from .defaults import CONFIG_PATH
 
 
-def config_path_option(function):
+def config_path_option(function) -> Callable:
+    """Wraps a function to add configuration path option."""
     return click.option(
         "-c",
         "--config",
@@ -14,7 +17,8 @@ def config_path_option(function):
     )(function)
 
 
-def config_options(function):
+def config_options(function) -> Callable:
+    """Wraps a function to add configuration options."""
     function = config_path_option(function)
     function = click.option(
         "-f", "--force", is_flag=True, help="Overwrite any existing configuration file."
diff --git a/manim_slides/defaults.py b/manim_slides/defaults.py
index 23689fc..13cbc70 100644
--- a/manim_slides/defaults.py
+++ b/manim_slides/defaults.py
@@ -3,7 +3,6 @@ import platform
 import cv2
 
 FONT_ARGS = (cv2.FONT_HERSHEY_SIMPLEX, 1, 255, 1, cv2.LINE_AA)
-PIXELS_PER_CHARACTER = 20
 FOLDER_PATH: str = "./slides"
 CONFIG_PATH: str = ".manim-slides.json"
 
diff --git a/manim_slides/present.py b/manim_slides/present.py
index 24a4053..5d500ce 100644
--- a/manim_slides/present.py
+++ b/manim_slides/present.py
@@ -37,7 +37,7 @@ class State(IntEnum):
 
 
 def now() -> int:
-    """Returns time.time() in seconds."""
+    """Returns time.time() in milliseconds."""
     return round(time.time() * 1000)
 
 
@@ -292,7 +292,7 @@ class Display:
             )
             cv2.resizeWindow(WINDOW_NAME, *resolution)
 
-    def resize_frame_to_screen(self, frame: np.ndarray):
+    def resize_frame_to_screen(self, frame: np.ndarray) -> np.ndarray:
         """
         Resizes a given frame to match screen dimensions.
 
diff --git a/manim_slides/wizard.py b/manim_slides/wizard.py
index f41f7b9..68e31b2 100644
--- a/manim_slides/wizard.py
+++ b/manim_slides/wizard.py
@@ -7,7 +7,7 @@ import numpy as np
 
 from .commons import config_options
 from .config import Config
-from .defaults import CONFIG_PATH, FONT_ARGS, PIXELS_PER_CHARACTER
+from .defaults import CONFIG_PATH, FONT_ARGS
 
 WINDOW_NAME = "Manim Slides Configuration Wizard"
 WINDOW_SIZE = (120, 620)
@@ -51,6 +51,7 @@ def init(config_path, force, merge, skip_interactive=False):
 
 
 def _init(config_path, force, merge, skip_interactive=False):
+    """Actual initialization code for configuration file, with optional interactive mode."""
 
     if os.path.exists(config_path):
         click.secho(f"The `{CONFIG_PATH}` configuration file exists")