Para evitar o aparecimento de avisos ao executar:
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, Input
regressor_2 = Sequential()
# Entrada moderna e recomendada
regressor_2.add(Input(shape=(1,)))
regressor_2.add(Dense(8, kernel_initializer='random_uniform',
activation='linear', use_bias=False))
regressor_2.add(Dense(8, kernel_initializer='random_uniform',
activation='linear', use_bias=False))
regressor_2.add(Dense(1, kernel_initializer='random_uniform',
activation='linear', use_bias=False))