'Create the TensorFlow variables for the model.
:param n_features: number of features
:return: self'

def _create_variables(self, n_features):

    w_name = 'weights'
    self.W = tf.Variable(tf.truncated_normal(shape=[n_features, self.num_hidden], stddev=0.1), name=w_name)
    tf.summary.histogram(w_name, self.W)
    bh_name = 'hidden-bias'
    self.bh_ = tf.Variable(tf.constant(0.1, shape=[self.num_hidden]), name=bh_name)
    tf.summary.histogram(bh_name, self.bh_)
    bv_name = 'visible-bias'
    self.bv_ = tf.Variable(tf.constant(0.1, shape=[n_features]), name=bv_name)
    tf.summary.histogram(bv_name, self.bv_)
