import tensorflow as tf


    with tf.variable_scope(scope, reuse=reuse):
        observations_ph = make_obs_ph("observation")
        stochastic_ph = tf.placeholder(tf.bool, (), name="stochastic")
        update_eps_ph = tf.placeholder(tf.float32, (), name="update_eps")
        update_param_noise_threshold_ph = tf.placeholder(tf.float32, (), name="update_param_noise_threshold")
        update_param_noise_scale_ph = tf.placeholder(tf.bool, (), name="update_param_noise_scale")
        reset_ph = tf.placeholder(tf.bool, (), name="reset")

        eps = tf.get_variable("eps", (), initializer=tf.constant_initializer(0))
        param_noise_scale = tf.get_variable("param_noise_scale", (), initializer=tf.constant_initializer(0.01), trainable=False)
        param_noise_threshold = tf.get_variable("param_noise_threshold", (), initializer=tf.constant_initializer(0.05), trainable=False)

        # Unmodified Q.
