Getting content of Excel file present in Github repository using python

I want to read the content of excel file stored in GitHub repository using python.

    access_token = '****'

def run_query(query, access_token):
    try:
        url = 'https://api.github.***.com/graphql'
        data = json.dumps({'query':query})
        req = urllib2.Request(url, data)
        req.add_header('Authorization', 'Bearer '+access_token)
        f = urllib2.urlopen(req, context=ssl._create_unverified_context())
        response = f.read()
        f.close()
        return response
    except Exception as e:
        print("Graphql fetch error in run_query function,%s",e)
        return '{"data":{"repository":{"object":{"text":"giterror"}}}}'

def createGraphqlQuery(ownerVal, repoVal, branchVal, pathVal):
    query = """
            {
              repository(owner: \""""+ownerVal+"""\", name: \""""+repoVal+"""\") {
                object(expression: \""""+branchVal+":"+pathVal+"""\") {    
                     ... on Blob {
                    text
                  }      
                }            
              }
            }
            """
    return query 

ownerVal = "user"
repoVal = "TestRepo"
branchVal = "master"
pathVal = "Teradata/testfile.xlsx"
query = createGraphqlQuery(ownerVal, repoVal, branchVal, pathVal)  
result = json.loads(run_query(query,access_token))
print(result)

I have tried the above code but it is only working for '.txt' file. is there any way to achieve this?

I tried using pandas also but it is giving the below error:

<urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1051)>

code:

df = pd.read_csv('https://github.***.com/user/TestRepo/tree/master/Teradata/testfile.xlsx',
                 sep='\t')
print(df)