I tried to use pushable range. When I tried to set pushable to number I get:

Type "number" is not assignable to parameter of type "boolean | undefined"

Same thing when I tried use RangeProps. So I changed pushable?: boolean; in Range.d.ts to pushable?: boolean | number; and it works fine.
Am I doing right (I'm new to development, sorry)?

I'm using:
Typescript 4.1.2
React 17.0.1
rc-slider 9.7.1