What does the notation $(1^-,2^-)$ mean in the ground-state nuclear spin of lithium $10$?

I am trying to get to grips with nuclear spin. However I note that many of the spin of isotopes can have many results. For example, if one looks on the Wikipedia page for the isotopes of lithium, the spin of $^{10}$Li, ground state, is quoted as $(1^-,2^-)$. And it says

The values of spin with weak assignment arguments are enclosed in parentheses.

So what does that mean, we don't know what the spin is? Does $^{10}$Li have two spins?