import pandas as pd

reviews_values = [
    [68,18], [81,19], [81,22], [15,75], [75,15], [17,72],
    [24,75], [21,91], [76, 6], [12,74], [18,83], [20,62],
    [21,82], [21,79], [84,15], [73,16], [88,25], [78,23],
    [32, 81], [77, 35]]
reviews = pd.DataFrame(reviews_values, columns=['Цена', 'Качество'])

visitors_count = len(reviews['Цена'].values)
visitor4 = reviews.loc[4].values

clients_1 = []
clients_2 = []
for client in list(reviews.values):
    if reviews[reviews['Цена'] > 40] and reviews[reviews['Цена'] < 60]:
        clients_1.append(client)
    else:
        clients_2.append(client)

print("Оценки пришедших с первого агрегатора:", clients_1)
print("Оценки пришедших со второго агрегатора:", clients_2)