julia> X = NullableArray([1:10...]);

julia> splice!(X.isnull, 1)
false

julia> X
10-element NullableArrays.NullableArray{Int64,1}:
    Nullable(1)
    Nullable(2)
    Nullable(3)
    Nullable(4)
    Nullable(5)
    Nullable(6)
    Nullable(7)
    Nullable(8)
    Nullable(9)
 #undef        

julia> length(X)
10

julia> length(X.isnull)
9

julia> A = [1:10...];

julia> X = NullableArray(A);

julia> splice!(A, 1)
1

julia> X
9-element NullableArrays.NullableArray{Int64,1}:
 Nullable(2) 
 Nullable(3) 
 Nullable(4) 
 Nullable(5) 
 Nullable(6) 
 Nullable(7) 
 Nullable(8) 
 Nullable(9) 
 Nullable(10)

julia> X.isnull
10-element Array{Bool,1}:
 false
 false
 false
 false
 false
 false
 false
 false
 false
 false