Yea check this:

```rust
    let mut scl = gpiob.new_pin(PinNum::P6, PinMode::Alt(AltFn::Af4));
  
    let mut sda = gpiob.new_pin(PinNum::P7, PinMode::Alt(AltFn::Af4));
    sda.output_type(OutputType::OpenDrain, &mut gpiob.regs);
```