Unable to read .xpt file from s3 raw bucket using pandas.read_sas

I am trying to read a SAS transport file(.xpt) which is present in S3 raw bucket using pandas.read_sas method but getting error

AttributeError: 'bytes' object has no attribute 'encode'

Here is the snippet of the code:

from boto.s3.connection import S3Connection
import boto3
import pandas as pd
import xport

"""after setting the S3 bucket details-this is how I am trying to read xpt"""

dr1=pd.read_sas("s3://" + mybucket_name + "/test.xpt", format="xport")

this is where I am getting error "AttributeError: 'bytes' object has no attribute 'encode'"