diff --git a/squirrelbattle/mapgeneration/randomwalk.py b/squirrelbattle/mapgeneration/randomwalk.py
index ef0997d..3595098 100644
--- a/squirrelbattle/mapgeneration/randomwalk.py
+++ b/squirrelbattle/mapgeneration/randomwalk.py
@@ -1,15 +1,22 @@
+# Copyright (C) 2020 by ÿnérant, eichhornchen, nicomarg, charlse
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 from enum import auto, Enum
 from random import choice, random, randint
+from typing import Tuple
+
 from ..interfaces import Map, Tile
 
 
-DEFAULT_PARAMS = {"split_chance" : .15,
-        "turn_chance" : .5,
-        "death_chance" : .1,
-        "max_walkers" : 15,
-        "width" : 100,
-        "height" : 100,
-        "fill" : .4}
+DEFAULT_PARAMS = {
+    "split_chance": .15,
+    "turn_chance": .5,
+    "death_chance": .1,
+    "max_walkers": 15,
+    "width": 100,
+    "height": 100,
+    "fill": .4,
+}
 
 
 class Directions(Enum):
@@ -20,16 +27,15 @@ class Directions(Enum):
 
 
 class Walker:
-
-    def __init__(self, x, y):
+    def __init__(self, x: int, y: int):
         self.x = x
         self.y = y
         self.dir = choice(list(Directions))
 
-    def random_turn(self):
+    def random_turn(self) -> None:
         self.dir = choice(list(Directions))
 
-    def next_pos(self):
+    def next_pos(self) -> Tuple[int, int]:
         if self.dir == Directions.up:
             return self.x, self.y + 1
         elif self.dir == Directions.down:
@@ -39,28 +45,29 @@ class Walker:
         elif self.dir == Directions.left:
             return self.x - 1, self.y
 
-    def move_in_bounds(self, width, height):
+    def move_in_bounds(self, width: int, height: int) -> None:
         nx, ny = self.next_pos()
         if 0 < nx < width and 0 < ny < height:
             self.x, self.y = nx, ny
 
-    def split(self):
+    def split(self) -> "Walker":
         child = Walker(self.x, self.y)
         child.dir = self.dir
         return child
 
 
 class Generator:
-
-    def __init__(self, params = DEFAULT_PARAMS):
+    def __init__(self, params: dict = None):
+        if params is None:
+            params = DEFAULT_PARAMS
         self.params = params
 
-    def run(self):
+    def run(self) -> Map:
         width, height = self.params["width"], self.params["height"]
-        walkers = [Walker(width//2, height//2)]
+        walkers = [Walker(width // 2, height // 2)]
         grid = [[Tile.EMPTY for _ in range(width)] for _ in range(height)]
         count = 0
-        while count < self.params["fill"] * width*height:
+        while count < self.params["fill"] * width * height:
             # because we can't add or remove walkers while looping over the pop
             # we need lists to keep track of what will be the walkers for the
             # next iteration of the main loop
@@ -77,10 +84,10 @@ class Generator:
                     next_walker_pop.append(walker)
 
             # we make sure to never kill all walkers
-            if next_walker_pop == []:
+            if not next_walker_pop:
                 next_walker_pop.append(choice(walkers))
 
-            # we use a second loop for spliting so we're not bothered by cases 
+            # we use a second loop for spliting so we're not bothered by cases
             # like a walker not spliting because we hit the population cap even
             # though the next one would have died and freed a place
             # not a big if it happened though
@@ -90,9 +97,8 @@ class Generator:
                         next_walker_pop.append(walker.split())
             walkers = next_walker_pop
 
-
-        start_x, start_y = randint(0, width-1), randint(0, height-1)
+        start_x, start_y = randint(0, width - 1), randint(0, height - 1)
         while grid[start_y][start_x] != Tile.FLOOR:
-            start_x, start_y = randint(0, width-1), randint(0, height-1)
+            start_x, start_y = randint(0, width - 1), randint(0, height - 1)
 
         return Map(width, height, grid, start_x, start_y)