code: def useTanhActivationFunction(self):
          
          self.activationFunction = self.activationFunctionTANH
          self.ACTPRIME = self.ACTPRIMETANH
          self.actDeriv = self.actDerivTANH
          for layer in self:
              layer.minTarget, layer.minActivation = -1.7159, -1.7159 
              layer.maxTarget, layer.maxActivation = 1.7159, 1.7159
docs: Change the network to use the hyperbolic tangent activation function for all layers.
          Must be called after all layers have been added.