Consistency in types when indexing ComponentVector with empty tuple

[bgctw]

When extracting a Sub-ComponentVector by indexing with a set of symbols, I sometimes encounter the case that the set of indices (computed somewhere else) is empty. For consistency, I expect the indexing to return the same type, i.e. an empty ComponentVector. But currently it returns a plain vector.

using ComponentArrays
using Test

cv = ComponentVector(k1 = 1.0, k2 = 2.0)
@test cv[(:k1, :k2)] == cv
@test cv[(:k1, )] == ComponentVector(k1 = 1.0)
@test cv[NTuple{0,Symbol}()] == ComponentVector{eltype(cv)}() # fails, should return ComponentVector
@test cv[()] == ComponentVector{eltype(cv)}()                 # discuss meaning 

What are the arguments for returning a plain vector instead of an empty ComponentVector?

Extending the KeepIndex to the empty tuple does not work for me, because I need a method to extract Sub-ComponentVectors that work consistently with a NTuple{N, Symbol} for any N.