diff --git a/src/Taggers.jl b/src/Taggers.jl
index 09520c158e8b17652265127b54eca57eccf1c818..4844907b16a1f466d7e159f6b199f0f6119d7335 100644
--- a/src/Taggers.jl
+++ b/src/Taggers.jl
@@ -227,9 +227,9 @@ function parsekwargs!(args, kwargs)
 end
 
 function run(tagger, switch, kwargs)
-    kwargs = Dict{AbstractString, Any}(kwargs)
-    kwargs["model_instance"] = tagger.model_instance
-    kwargs["sandbox"] = tagger.sandbox
+    kwargs = Dict{Symbol, Any}(kwargs)
+    kwargs[:model_instance] = tagger.model_instance
+    kwargs[:sandbox] = tagger.sandbox
     args = Any[]
     parsekwargs!(args, kwargs)
     cmd = tagging_backend_command(tagger)
@@ -245,8 +245,8 @@ end
 predict(tagger::Tagger; kwargs...) = run(tagger, "predict", kwargs)
 
 function finetune(tagger::Tagger; original_instance=nothing, kwargs...)
-    kwargs = Dict{AbstractString, Any}(kwargs)
-    kwargs["original_model_instance"] = original_instance
+    kwargs = Dict{Symbol, Any}(kwargs)
+    kwargs[:original_model_instance] = original_instance
     ret = run(tagger, "finetune", kwargs)
     @assert isdir(modeldir(tagger))
     return ret