How to get final Neural Network error with NeuroLab?

Question

I already know how to train a neural net with NeuroLab and get the error every X epochs, but I want to get the final error after training the net.

nn = nl.net.newff([[min_val, max_val]], [40, 26, 1])

# Gradient descent
nn.trainf = nl.train.train_gd

# Train the neural network
error_progress = nn.train(data, labels, epochs=6000, show=100, goal=0.0005)

# CODE TO GET THE ERROR AFTER TRAINING HERE
# final_error = ?

EDIT: By final_error I mean the final value of the Error variable that the net.train command plots (ONLY the error, not the complete string, as it plots in the following format).

Epoch: 1700; Error: 0.0005184049;

Answer 1

Okay, so the best way I have found until now is to save the error progress and then get the last item in the array.

# Train the neural network
error_progress = net.train(data, labels, epochs=10000, show=100, goal=0.01)

# THIS IS THE LAST ERROR VALUE THE NET OUTPUTS
final_error = error_progress[-1]