Not able to call class function

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Python3.6

#!"C:\\Users\\M1032959\\AppData\\Local\\Programs\\Python\\Python36\\python.exe"

import cgi, cgitb
import _mysql
import sys
import logging

print ("Content-Type: text/html")
print ("""
  <TITLE>Bank login</TITLE>
""")

log_fname = "login_Details.log"

logging.basicConfig(filename=log_fname,
                    filemode='a',
                    level=logging.DEBUG,
                    format='%(asctime)s : %(levelname)s => %(message)s',
                    datefmt='%Y-%m-%d %H:%M:%S'
                   )

frmEmp = cgi.FieldStorage()

try:
    conn = _mysql.connect("localhost", "root", "", "bank_details")
    logging.info('connection details:%s',conn)
except Exception as e:
    print ("<br>Connection Error-> e</br>")
    logging.error('connection error: %s',e)
sys.exit()

class UserBankData:
    username = []
    upassword = []    
    def __init__(self):
        username = self.username
        upassword = self.upassword            
    def validateData(self):
        username = frmEmp.getvalue("uname")
        upassword = frmEmp.getvalue("upassword")
        # serch username and password in database
        sql = "SELECT uname,pass FROM login_check"
        conn.query(sql)
        login = 0
        # Store the result set
        all_recs = conn.store_result()
        rec = all_recs.fetch_row()
        while (rec):
          for ename, epass in rec:
            ename = str(ename, 'utf-8')
            epass = str(epass, 'utf-8')
            if(username == ename and upassword == epass):
                login =1
                logging.info("User name and Password is correct")
                break
            rec = all_recs.fetch_row()
        if(login == 0):
            logging.error("User name and Password is not correct.. Please enter proper details")
            print("User name and Password is not correct.. Please enter proper details")
            
obj = UserBankData()
obj.validateData()
conn.close()

What I have tried:

I am new in python and i wrote giving code in python. When i run code it is not giving any error but it not calling class function validateData().