Unable to make database connection using python adodbapi library

I am trying to make SQL Server database connection using python library adodbapi and latest OLEDB provider using below code-

import adodbapi
import configparser

def try_connection():    
    _SERVER_NAME = "SERVERNAME"
    _DATABASE = "TESTDB"
    _USERNAME = "TERSTUSER"
    _PASSWORD = "TESTPWD"  

    conn = adodbapi.connect("PROVIDER=MSOLEDBSQL;Data Source={0};Database={1};UID={2};PWD={3};".format(_SERVER_NAME,_DATABASE,_USERNAME,_PASSWORD))
    cursor = conn.cursor()

print( try_connection() )

But, I am unable to make connection. I am getting below huge trace error which I am unable to figure out:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\adodbapi\adodbapi.py", line 97, in make_COM_connecter
    c = Dispatch('ADODB.Connection') #connect _after_ CoIninialize v2.1.1 adamvan
NameError: name 'Dispatch' is not defined

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\adodbapi\adodbapi.py", line 116, in connect
    co.connect(kwargs)
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\adodbapi\adodbapi.py", line 266, in connect
    self.connector = connection_maker()
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\adodbapi\adodbapi.py", line 99, in make_COM_connecter
    raise api.InterfaceError ("Windows COM Error: Dispatch('ADODB.Connection') failed.")
adodbapi.apibase.InterfaceError: Windows COM Error: Dispatch('ADODB.Connection') failed.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "TestAdodb.py", line 41, in <module>
    print( try_connection() )
  File "TestAdodb.py", line 18, in try_connection
    conn = adodbapi.connect("PROVIDER=MSOLEDBSQL;Data Source={0};Database={1};UID={2};PWD={3};".format(_SERVER_NAME,_DATABASE,_USERNAME,_PASSWORD))
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\adodbapi\adodbapi.py", line 120, in connect
    raise api.OperationalError(e, message)
adodbapi.apibase.OperationalError: (InterfaceError("Windows COM Error: Dispatch('ADODB.Connection') failed.",), 'Error opening connection to "PROVIDER=MSOLEDBSQL;Data Source=SERVERNAME;Database=TESTDB;UID=TERSTUSER;PWD=TESTPWD;"')

Please can anyone let me know what is wrong/missing in my connection string?

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