Not Getting values of tensor in function which is called from dataset.map in tensorflow

Question

I am trying to get values of tensor from function which is called by map function. But I am getting this error.

tensorflow.python.framework.errors_impl.InvalidArgumentError: You must feed a value for placeholder tensor 'args_0' with dtype string [[{{node args_0}}]]

my code is as follows

In my main function:

# created instance of Preprocess class
preprocess = Preprocessor(is_train, TOTAL_CLASSES, OUTPUT_SHAPE)

# all the tfrecords which is present in ./tfrecords folder we will gate
dataset = tf.data.Dataset.list_files("./tfrecords")

# we will comprises it into one
dataset = tf.data.TFRecordDataset(dataset)

# Here I am mapped __call__ method which is present in Preprocess class
dataset = dataset.map(preprocess, num_parallel_calls=tf.data.experimental.AUTOTUNE)

Now in Preprocess class call method I am getting error This is my preprocess class. In call function I am getting error.

class Preprocessor(object):
    def __init__(self, is_train, num_classes, output_shape=(416, 416)):
        self.is_train = is_train
        self.num_classes = num_classes
        self.output_shape = output_shape

    def __call__(self, example):
        features = self.parse_tfexample(example)
        encoded = features['image/encoded']
        image = tf.io.decode_jpeg(encoded)
        image = tf.cast(image, tf.float32)

        sess = tf.Session()

        # at this line I am getting error
        print(sess.run(image))

How I can resolve this problem. If I comment print(sess.run(image)) this line all the code work properly. But I want values of tensors in maped function.