When closing a trade, can the size be specified as larger than an integer?

[IMYin]

My trading target is futures, with a minimum trading size of 1 lot and a minimum unit of 300 per lot. When I trigger a certain signal, I only want to reduce my position instead of closing it completely. However, the parameter in the close function is a proportion value. So, if I hold a position of 7 lots and my size is 2100, the parameter set for self.position.close(portion=6/7), which is not wrong. But the result is that my position is 301, which is incorrect and causes a chain reaction of position errors later on.

The sample shown in the picture is incorrect.

The correct one should look like the following.

So I am wondering if it is possible to adjust the setting of the portion parameter?