diff --git a/README.md b/README.md
index c15eccda..893ebd65 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ model = ICNFModel(
     icnf;
     batch_size = 256, # have bigger batchs
     # n_epochs = 100, # have less epochs
-    # optimizers = [Lion()], # use a different optimizer
+    # optimizers = (Lion(),), # use a different optimizer
     # adtype = AutoForwardDiff(), # use ForwardDiff
 )
 mach = machine(model, df)
diff --git a/src/cores/core_cond_icnf.jl b/src/cores/core_cond_icnf.jl
index ddba2d88..8f1c4cd8 100644
--- a/src/cores/core_cond_icnf.jl
+++ b/src/cores/core_cond_icnf.jl
@@ -6,7 +6,7 @@ mutable struct CondICNFModel <: MLJICNF
     m::AbstractICNF
     loss::Function
 
-    optimizers::AbstractVector
+    optimizers::Tuple
     n_epochs::Int
     adtype::ADTypes.AbstractADType
 
@@ -19,7 +19,7 @@ end
 function CondICNFModel(
     m::AbstractICNF{<:AbstractFloat, CM},
     loss::Function = loss;
-    optimizers::AbstractVector = Any[PolyOpt(),],
+    optimizers::Tuple = (PolyOpt(),),
     n_epochs::Int = 300,
     adtype::ADTypes.AbstractADType = AutoZygote(),
     use_batch::Bool = true,
diff --git a/src/cores/core_icnf.jl b/src/cores/core_icnf.jl
index 93af59d2..49cd67e6 100644
--- a/src/cores/core_icnf.jl
+++ b/src/cores/core_icnf.jl
@@ -6,7 +6,7 @@ mutable struct ICNFModel <: MLJICNF
     m::AbstractICNF
     loss::Function
 
-    optimizers::AbstractVector
+    optimizers::Tuple
     n_epochs::Int
     adtype::ADTypes.AbstractADType
 
@@ -19,7 +19,7 @@ end
 function ICNFModel(
     m::AbstractICNF{<:AbstractFloat, CM},
     loss::Function = loss;
-    optimizers::AbstractVector = Any[PolyOpt(),],
+    optimizers::Tuple = (PolyOpt(),),
     n_epochs::Int = 300,
     adtype::ADTypes.AbstractADType = AutoZygote(),
     use_batch::Bool = true,