Among the functions for reshaping arrays (reshape, permutedims, dropdims), dropdims is the only one that accepts dims as a keyword argument — the rest take dimensions as a positional argument.

julia> permutedims([1 2 3], (2, 1))
3×1 Array{Int64,2}:
 1
 2
 3

Also, it feels a little redundant to have to say "dims" twice, once in the argument and once in the name of the function:

julia> dropdims([1 2 3], dims=(1,))
3-element Array{Int64,1}:
 1
 2
 3

julia> dropdims([1 2 3], (1,))
ERROR: MethodError: no method matching dropdims(::Array{Int64,2}, ::Tuple{Int64})

Note: It's possible to make this change backwards-compatibly by accepting both the keyword and positional argument.