<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def convert_to_flat(self, builder):
 """ In this conversion, we always want to return a valid flatbuffer pointer even if all the contents are blank because sometimes we need to put empty car states into the car list to make the indices line up. """

        physics_offset = None if self.physics is None else self.physics.convert_to_flat(builder)

        DesiredCarState.DesiredCarStateStart(builder)
        if physics_offset is not None:
            DesiredCarState.DesiredCarStateAddPhysics(builder, physics_offset)
        if self.boost_amount is not None:
            DesiredCarState.DesiredCarStateAddBoostAmount(builder, Float.CreateFloat(builder, self.boost_amount))
        if self.jumped is not None:
            DesiredCarState.DesiredCarStateAddJumped(builder, Bool.CreateBool(builder, self.jumped))
        if self.double_jumped is not None:
            DesiredCarState.DesiredCarStateAddDoubleJumped(builder, Bool.CreateBool(builder, self.double_jumped))
        return DesiredCarState.DesiredCarStateEnd(builder)