code: def define_params(self):
          '''
          Define parameters.
          '''
          input_dim = self.input_dim
          hidden_dim = self.hidden_dim
          prefix = self.name
          self.w_matrix = tf.Variable(tf.random_normal([input_dim, 3 * hidden_dim], stddev=0.1),
                                      name='/'.join([prefix, 'W']))
          self.U = tf.Variable(tf.random_normal([hidden_dim, 3 * hidden_dim], stddev=0.1),
                               name='/'.join([prefix, 'U']))
          self.bias = tf.Variable(tf.random_normal([1, 3 * hidden_dim], stddev=0.1),
                                  name='/'.join([prefix, 'b']))
          return self define_params(self):
          '''
          Define parameters.
          '''
          input_dim = self.input_dim
          hidden_dim = self.hidden_dim
          prefix = self.name
          self.w_matrix = tf.Variable(tf.random_normal([input_dim, 3 * hidden_dim], stddev=0.1),
                                      name='/'.join([prefix, 'W']))
          self.U = tf.Variable(tf.random_normal([hidden_dim, 3 * hidden_dim], stddev=0.1),
                               name='/'.join([prefix, 'U']))
          self.bias = tf.Variable(tf.random_normal([1, 3 * hidden_dim], stddev=0.1),
                                  name='/'.join([prefix, 'b']))
          return self
docs: Define parameters.