Smart Contract Lottery throws "VirtualMachineError: revert" when ending the lottery - solidity

Question

I have been following Solidity, Blockchain, and Smart Contract Course – Beginner to Expert Python Tutorial (https://www.youtube.com/watch?v=M576WGiDBdQ&t=28658s). When I run deploy_lottery.py, it breaks down while ending the lottery. Here is the snippet of code in Lottery.sol
function endLottery() public onlyOwner {
lottery_state = LOTTERY_STATE.CALCULATING_WINNER;
bytes32 requestId = requestRandomness(keyhash, fee);
emit RequestedRandomness(requestId);
}
Here is the code snippet in deploy_lottery.py
def end_lottery():
account = get_account()
lottery = Lottery[-1]
# fund the contract
# then end the lottery
tx = fund_with_link(lottery.address)
tx.wait(1)
print("Here")
ending_transaction = lottery.endLottery({"from": account})
print("ended transaction")
ending_transaction.wait(1)
time.sleep(180)
print(f"{lottery.recentWinner()} is the new winner!")
I have also attached snapshot of error. Thanks in advance.
https://i.stack.imgur.com/yU8jC.png

Answer 1

I have been stuck with the same error. The solution was to fund the contract with sufficient token. For testing I did
amount=5000000000000000000 in fund_with_link()
def fund_with_link(contract_address, account=None, link_token=None, amount=5000000000000000000):
account = account if account else get_account()
link_token = link_token if link_token else get_contract("link_token")
tx = link_token.transfer(contract_address, amount, {"from": account})
tx.wait(1)
print("Contract Funded")
return tx