diff --git a/src/config.jl b/src/config.jl
index 956c259..0dcf901 100644
--- a/src/config.jl
+++ b/src/config.jl
@@ -28,9 +28,9 @@ const _DEFAULT_PARAMS = Dict{Symbol,Any}(
 const DEFAULT_PARAMS = deepcopy(_DEFAULT_PARAMS) # might be changed at runtime
 
 """
-    set_chunk_defaults!(k::Symbol, v::Any) = DEFAULT_PARAMS[k]= v
-    set_chunk_defaults!(kv::Pair{Symbol,Any}...) = for (k,v) in kv; set_chunk_defaults!(k, v); end
-    set_chunk_defaults!(opts::AbstractDict{Symbol,Any}) = merge!(DEFAULT_PARAMS, opts)
+    set_chunk_defaults!(k, v)
+    set_chunk_defaults!(kv::Pair...)
+    set_chunk_defaults!(opts::AbstractDict)
 
 Set default options for code chunks, use [`get_chunk_defaults`](@ref) to see the current values.
 
@@ -39,9 +39,9 @@ E.g.: all the three examples below will set default `dpi` to `200` and `fig_widt
 - `set_chunk_defaults!(:dpi => 200, :fig_width => 8)`
 - `set_chunk_defaults!(Dict(:dpi => 200, :fig_width => 8))`
 """
-set_chunk_defaults!(k::Symbol, v::Any) = DEFAULT_PARAMS[k]= v
-set_chunk_defaults!(kv::Pair{Symbol,Any}...) = for (k,v) in kv; set_chunk_defaults!(k, v); end
-set_chunk_defaults!(opts::AbstractDict{Symbol,Any}) = merge!(DEFAULT_PARAMS, opts)
+set_chunk_defaults!(k, v) = DEFAULT_PARAMS[k]= v
+set_chunk_defaults!(kv::Pair...) = for (k,v) in kv; set_chunk_defaults!(k, v); end
+set_chunk_defaults!(opts::AbstractDict) = merge!(DEFAULT_PARAMS, opts)
 
 """
     get_chunk_defaults()