How do I interpret this error?

I can’t figure what this means. It looks like it says it can’t find exactly what it’s seeing as the closest candidate.

julia> ThinkStats.probs(t)
ERROR: MethodError: no method matching probs(::Main.ThinkStats.CatDist)
Closest candidates are:
probs(::Main.ThinkStats.CatDist) at ~/src/bayes_in_julia/ThinkStats.jl:13