def _variable_on_cpu(name, shape, initializer):
    with tf.device('/cpu:0'):
        var = tf.get_variable(name, shape, initializer=initializer)
    return var
def _variable_on_cpu(name, shape, initializer):
    with tf.device('/cpu:0'):
        var = tf.get_variable(name, shape, initializer=initializer)
    return var