My guess is that if you call it with a boolean argument, it returns `this` for chaining purposes. Otherwise it returns the current value of `_connectorsEnabled`. There are two declarations for the different usages, and then the actual implementation can return `any`. It is a bit strange.

edit - see also line 24, for the declaration of the usage without an argument: https://github.com/palantir/plottable/blob/develop/src/plots...