Lambdify, no method matching getindex

Does anyone know how to resolve the following issue of “lamdify”?

julia> using SymPy
julia> @syms x, y, z
julia> xx = zeros(Sym, 2, 1)
julia> xx[1] = xyz
julia> xx[2] = x^2
julia> xx = xx.*[1,1]
julia> fxx = lambdify(xx, (x, y, z))
julia> fxx[1,1,1]
ERROR: MethodError: no method matching getindex(::SymPy.var"#122#124"{Matrix{SymPy.var"#118#119"}}, ::Int64, ::Int64, ::Int64)
[1] top-level scope
@ REPL[103]:1

fxx is a function that returns a 2x1 matrix:

julia> fxx = lambdify(xx, (x, y, z))
#122 (generic function with 1 method)

julia> fxx(1,1,1)
2×1 Matrix{Int64}:

Thanks. Yes, it should be called as a function.