Parameterizing python codes in power query Advance editor

Hello Folks,

I have a python code which needed to be parameterized in power bi . You can see the below python code . I have three parameters called user, pw and server_address

from tableau_api_lib import TableauServerConnection
from tableau_api_lib.utils.querying import get_views_dataframe

username = "" & user & ""'
password = '"" & pw & ""'
server = '"" & server_address & ""'

tableau_server_config_ft = {
    'my_env': {
        'server': server ,
        'username': username,
        'password': password
    }
}  

conn = TableauServerConnection(tableau_server_config_ft, env='my_env')
conn.sign_in()

But If i put my credentials in the code as it is, this works. 

Can somebody help me regarding this?