Function py_probability_to_bet 

pub fn py_probability_to_bet(
    probability: Decimal,
    volume: Decimal,
    side: OrderSide,
) -> PyResult<Bet>

Converts a probability and volume into a Bet.

For a BUY side, this creates a BACK bet; for SELL, a LAY bet.

Errors

Returns an error if probability is zero or the conversion overflows.