<s> import Neuron <EOL> import math <EOL> class SigmoidNeuron ( Neuron . Neuron ) : <EOL> def Activate ( self , x ) : <EOL> return <NUM_LIT:1> / ( <NUM_LIT:1> + math . exp ( - x ) ) <EOL> def Derivative ( self , x ) : <EOL> act = self . Activate ( x ) <EOL> return act * ( <NUM_LIT:1> - act ) </s>
