The swapTo() function should not be payable since the WBNB-SPARTA pool should not receive BNB, but WBNB. The router swap functions handles the wrapping and unwrapping of BNB.
Furthermore, the swapTo() will not detect any deposited BNB, so any swapTo() calls that have msg.value > 0 will have their BNB permanently locked in the pool contract.
Recommend removing payable keyword in swapTo().
