diff --git a/Project.toml b/Project.toml
index c7504a4..c7cecd0 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "OMEinsumContractionOrders"
 uuid = "6f22d1fd-8eed-4bb7-9776-e7d684900715"
 authors = ["Jin-Guo Liu", "Pan Zhang"]
-version = "0.8.1"
+version = "0.8.2"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
diff --git a/src/json.jl b/src/json.jl
index f32d7b9..8014887 100644
--- a/src/json.jl
+++ b/src/json.jl
@@ -31,7 +31,7 @@ function _fromdict(dict)
     end
     ne = fromdict(LT, dict["tree"])
     if haskey(dict, "slices")
-        return SlicedEinsum(_convert.(LT, dict["slices"]), ne)
+        return SlicedEinsum(LT[_convert(LT, l) for l in dict["slices"]], ne)
     else
         return ne
     end
@@ -68,4 +68,4 @@ function einsfromdict(::Type{LT}, dict::Dict) where LT
 end
 
 _convert(::Type{LT}, x) where LT = convert(LT, x)
-_convert(::Type{Char}, x::String) where LT = (@assert length(x)==1; x[1])
+_convert(::Type{Char}, x::String) = (@assert length(x)==1; x[1])
diff --git a/src/treesa.jl b/src/treesa.jl
index c63f27e..fb31557 100644
--- a/src/treesa.jl
+++ b/src/treesa.jl
@@ -454,7 +454,7 @@ function ExprTree(code::NestedEinsum)
     _exprtree(code, _label_dict(code))
 end
 function _exprtree(code::NestedEinsum, labels)
-    @assert length(code.args) == 2
+    @assert length(code.args) == 2 "einsum contraction not in the binary form, got number of arguments: $(length(code.args))"
     ExprTree(map(enumerate(code.args)) do (i,arg)
         if isleaf(arg)  # leaf nodes
             ExprTree(ExprInfo(getindex.(Ref(labels), getixsv(code.eins)[i]), arg.tensorindex))