diff --git a/src/p2lab/genetic/operations.py b/src/p2lab/genetic/operations.py
index a117fc7..ebf814a 100644
--- a/src/p2lab/genetic/operations.py
+++ b/src/p2lab/genetic/operations.py
@@ -146,7 +146,7 @@ def locus_swap(
     team2: list[str],
     num_pokemon: int,
     allow_all: bool,
-    locus: int = None,
+    locus: int | None = None,
 ) -> tuple(list[str], list[str]):
     """
     A method of performing the crossover. Pick a 'locus' point: this
@@ -194,7 +194,7 @@ def slot_swap(
     team2: list[str],
     num_pokemon: int,
     allow_all: bool,
-    k: int = None,
+    k: int | None = None,
 ) -> tuple(list[str], list[str]):
     """
     A method of performing the crossover. This method randomly
@@ -294,7 +294,7 @@ def mutate(
     mutate_prob: float | np.ndarray,
     pokemon_population: list[str],
     allow_all: bool,
-    k: int = None,
+    k: int | None = None,
 ):
     """
     A mutation operation. At random, k members of a team are swapped with k
@@ -362,7 +362,7 @@ def fitness_mutate(
     fitness: np.array,
     pokemon_population: list[str],
     allow_all: bool,
-    k: int = None,
+    k: int | None = None,
 ):
     """
     A mutation operation. Does the same as regular mutation, except that
diff --git a/src/p2lab/pokemon/pokefactory.py b/src/p2lab/pokemon/pokefactory.py
index 9837e49..96406f8 100644
--- a/src/p2lab/pokemon/pokefactory.py
+++ b/src/p2lab/pokemon/pokefactory.py
@@ -21,7 +21,7 @@ def __init__(self, gen=1, drop_forms=True):
             self.dex2mon = {
                 int(self.dex.pokedex[m]["num"]): m
                 for m in self.dex.pokedex
-                if "forme" not in self.dex.pokedex[m].keys()
+                if "forme" not in self.dex.pokedex[m]
             }
         else:
             self.dex2mon = {
@@ -68,7 +68,7 @@ def make_pokemon(self, dexnum=None, generate_moveset=False, **kwargs):
             raise ValueError(msg)
         if dexnum is None:
             dexnum = np.random.choice(list(self.dex2mon.keys()))
-        if generate_moveset or "moves" not in kwargs.keys():
+        if generate_moveset or "moves" not in kwargs:
             poss_moves = self.get_allowed_moves(dexnum)
             moves = (
                 np.random.choice(poss_moves, 4, replace=False)
@@ -76,16 +76,16 @@ def make_pokemon(self, dexnum=None, generate_moveset=False, **kwargs):
                 else poss_moves
             )
             kwargs["moves"] = moves
-        if "ivs" not in kwargs.keys():
+        if "ivs" not in kwargs:
             ivs = [31] * 6
             kwargs["ivs"] = ivs
-        if "evs" not in kwargs.keys():
+        if "evs" not in kwargs:
             # TODO: implement EV generation better
             evs = [510 // 6] * 6
             kwargs["evs"] = evs
-        if "level" not in kwargs.keys():
+        if "level" not in kwargs:
             kwargs["level"] = 100
-        if "ability" not in kwargs.keys():
+        if "ability" not in kwargs:
             kwargs["ability"] = np.random.choice(
                 list(self.get_allowed_abilities(dexnum).values())
             )