human
Solve the following python programming problem given the following code:
@gof.local_optimizer([sigmoid])
def local_ultra_fast_sigmoid(node):
assistant
#Here is the Python code you requested.

    """When enabled, change all sigmoid to ultra_fast_sigmoid.
    For example do mode.including(\local_ultra_fast_sigmoid\)
    or use the Theano flag optimizer_including=local_ultra_fast_sigmoid.
    This speeds up the sigmoid op by using an approximation.
    This is done after the stabilization and specialize phases
    to avoid interacting with them.
    """
    if (isinstance(node.op, tensor.Elemwise) and (node.op.scalar_op == scalar_sigmoid)):
        out = ultra_fast_sigmoid(node.inputs[0])
        copy_stack_trace(node.outputs[0], out)
        def values_eq_approx_remove_low_prec(a, b):
            return tensor.TensorType.values_eq_approx(a, b, atol=0.02)
        out.tag.values_eq_approx = values_eq_approx_remove_low_prec
        return [out]