diff --git a/lab2/gen.py b/lab2/gen.py
index f6fab19..1ccf957 100644
--- a/lab2/gen.py
+++ b/lab2/gen.py
@@ -16,7 +16,7 @@ from numpy.typing import NDArray
 type Chromosome = NDArray[np.float64]
 type Population = list[Chromosome]
 type Fitnesses = NDArray[np.float64]
-type FitnessFn = Callable[[Chromosome], Fitnesses]
+type FitnessFn = Callable[[Chromosome], np.float64]
 type CrossoverFn = Callable[[Chromosome, Chromosome], tuple[Chromosome, Chromosome]]
 type MutationFn = Callable[[Chromosome], Chromosome]
 
@@ -185,7 +185,7 @@ def plot_fitness_surface(
     x_max: Chromosome,
     ax: Axes3D,
     num_points: int = 100,
-) -> None:
+):
     """Рисует поверхность функции фитнеса в 3D."""
     assert (
         x_min.shape == x_max.shape == (2,)
diff --git a/lab2/main.py b/lab2/main.py
index 0f3432e..5099c1a 100644
--- a/lab2/main.py
+++ b/lab2/main.py
@@ -3,7 +3,7 @@ import numpy as np
 from gen import GARunConfig, genetic_algorithm
 
 
-def fitness_function(chromosome: np.ndarray) -> np.ndarray:
+def fitness_function(chromosome: np.ndarray) -> np.float64:
     return chromosome[0] ** 2 + 2 * chromosome[1] ** 2