How to use the babi.model.Embedder function in babi

import tensorflow as tf

from babi.base_model import BaseTower, BaseRunner
from my.tensorflow.nn import linear
import numpy as np


class Embedder(object):
    def __call__(self, content):
        raise Exception()


class VariableEmbedder(Embedder):
    def __init__(self, params, wd=0.0, initializer=None, name="variable_embedder"):
        V, d = params.vocab_size, params.hidden_size
        with tf.variable_scope(name):
            self.emb_mat = tf.get_variable("emb_mat", dtype='float', shape=[V, d], initializer=initializer)
            # TODO : not sure wd is appropriate for embedding matrix
            if wd:
                weight_decay = tf.mul(tf.nn.l2_loss(self.emb_mat), wd, name='weight_loss')
                tf.add_to_collection('losses', weight_decay)

    def __call__(self, word, name="embedded_content"):
        out = tf.nn.embedding_lookup(self.emb_mat, word, name=name)
        return out


class PositionEncoder(object):
    def __init__(self, max_sent_size, hidden_size):