Не выводится график в Jupyter

import pandas as pd
import seaborn as sns
import sklearn
import numpy as np
import matplotlib.pyplot as plt
from sklearn.datasets import make_moons
from sklearn.model_selection import train_test_split
from sklearn.neighbors import KNeighborsClassifier
 
 
X, y = make_moons(n_samples = 1000, noise = 0.5, random_state = 10)
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size = 0.5, random_state = 10, shuffle=True)
sns.scatterplot(x = X[:, 0], y = X[:, 1], c = y)
 
from sklearn.model_selection import GridSearchCV
from sklearn.model_selection import KFold
from sklearn.metrics import mean_squared_error
 
searcher = GridSearchCV(KNeighborsClassifier(), param_grid = {
'n_neighbors' : [i for i in range(1,21)],                                                              
'weights' : ['uniform', 'distance'], 'p' : [1,2,3]
},
cv = KFold(n_splits=5, random_state=10, shuffle=True))
 
searcher.fit(X_train, y_train)
accuracy = mean_squared_error(y_test, searcher.predict(X_test))
 
 
# часть задания по теме вопроса:
 
def train_grid_search(X, y):
    def_searcher = GridSearchCV(KNeighborsClassifier(), param_grid = 
                                {'n_neighbors' : [i for i in range(1,21)]})
 
    def_searcher.fit(X_train,y_train)
    return def_searcher.cv_results_['mean_test_score']
 
mean_test_scores = []
for i in range(1000):
    X, y = make_moons(n_samples = 1000, noise = 0.5)
    mean_test_score = train_grid_search(X, y)
    mean_test_scores.append(mean_test_score)
 
mean_test_scores = np.array(mean_test_scores)
plt.plot(np.arange(1, 21), np.mean(mean_test_scores, axis = 0))

import numpy as np
import matplotlib.pyplot as plt
 
rng = np.arange(50)
rnd = np.random.randint(0, 10, size=(3, rng.size))
yrs = 1950 + rng
 
fig, ax = plt.subplots(figsize=(5, 3))
ax.stackplot(yrs, rng + rnd, labels=['Eastasia', 'Eurasia', 'Oceania'])
ax.set_title('Combined debt growth over time')
ax.legend(loc='upper left')
ax.set_ylabel('Total debt')
ax.set_xlim(xmin=yrs[0], xmax=yrs[-1])
fig.tight_layout()
 
plt.show()