diff --git a/src/flatten.jl b/src/flatten.jl
index a4c95a6..3caea79 100644
--- a/src/flatten.jl
+++ b/src/flatten.jl
@@ -19,7 +19,7 @@ function flatten end
 
 flatten(x) = flatten(Float64, x)
 
-function flatten(::Type{T}, ::Nothing) where {T<:Real} 
+function flatten(::Type{T}, ::Nothing) where {T<:Real}
     v = T[]
     unflatten_to_Nothing(::Vector{T}) = nothing
     return v, unflatten_to_Nothing