Place order is not working

I am getting unknown tradingsymbol for the following place order

kite.place_order(tradingsymbol='BANKNIFTY2120337600PE',
exchange=kite.EXCHANGE_NFO,
transaction_type= 'BUY',
quantity=25,
order_type=kite.ORDER_TYPE_MARKET,
product=kite.PRODUCT_MIS,
variety=kite.VARIETY_REGULAR)


What am I doing wrong?

What is the format for Banknifty weekly and monthly expiry

BANKNIFTY<YY><M><DD><STRIKE><CE/PE> For weekly?