Suppose I’m looping over a large vector of distributions from Distributions.jl.

How can I automatically find how many parameters there are in a distribution?

I want a function `nparams(d)`

where:

`nparams(Normal)=2`

since Normal(μ,σ)

`nparams(BetaBinomial)=3`

since BetaBinomial(n,α,β)