diff --git a/Project.toml b/Project.toml
index c6588f0..1bef4ba 100644
--- a/Project.toml
+++ b/Project.toml
@@ -26,7 +26,7 @@ SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 DataDeps = "0.7"
 Distributions = "0.25"
 DocStringExtensions = "0.9"
-Flux = "0.14"
+Flux = "0.16"
 Graphs = "1.11"
 HiGHS = "1.9"
 Images = "0.26"
diff --git a/src/DecisionFocusedLearningBenchmarks.jl b/src/DecisionFocusedLearningBenchmarks.jl
index 21265e3..118da5b 100644
--- a/src/DecisionFocusedLearningBenchmarks.jl
+++ b/src/DecisionFocusedLearningBenchmarks.jl
@@ -38,7 +38,7 @@ using .PortfolioOptimization
 export AbstractBenchmark, DataSample
 export generate_dataset
 export generate_statistical_model
-export generate_maximizer
+export generate_maximizer, maximizer_kwargs
 export plot_data
 export compute_gap
 
diff --git a/src/Utils/Utils.jl b/src/Utils/Utils.jl
index 65f17d8..1426a04 100644
--- a/src/Utils/Utils.jl
+++ b/src/Utils/Utils.jl
@@ -15,6 +15,7 @@ export DataSample
 export AbstractBenchmark
 export generate_dataset,
     generate_statistical_model, generate_maximizer, plot_data, compute_gap
+export maximizer_kwargs
 export grid_graph, get_path, path_to_matrix
 export neg_tensor, squeeze_last_dims, average_tensor
 
diff --git a/src/Utils/data_sample.jl b/src/Utils/data_sample.jl
index 33b7bb4..1afefbb 100644
--- a/src/Utils/data_sample.jl
+++ b/src/Utils/data_sample.jl
@@ -6,7 +6,9 @@ Data sample data structure.
 # Fields
 $TYPEDFIELDS
 """
-@kwdef struct DataSample{F,S,C,I}
+@kwdef struct DataSample{
+    F<:AbstractArray,S<:Union{AbstractArray,Nothing},C<:Union{AbstractArray,Nothing},I
+}
     "features"
     x::F
     "target cost parameters (optional)"
diff --git a/src/Utils/interface.jl b/src/Utils/interface.jl
index 44b21fa..c750c97 100644
--- a/src/Utils/interface.jl
+++ b/src/Utils/interface.jl
@@ -55,10 +55,52 @@ function compute_gap end
 """
 $TYPEDSIGNATURES
 
+For simple benchmarks where there is no instance object, maximizer does not need any keyword arguments.
+"""
+function maximizer_kwargs(
+    ::AbstractBenchmark, sample::DataSample{F,S,C,Nothing}
+) where {F,S,C}
+    return NamedTuple()
+end
+
+"""
+$TYPEDSIGNATURES
+
+For benchmarks where there is an instance object, maximizer needs the instance object as a keyword argument.
+"""
+function maximizer_kwargs(::AbstractBenchmark, sample::DataSample)
+    return (; instance=sample.instance)
+end
+
+"""
+$TYPEDSIGNATURES
+
 Default behaviour of `objective_value`.
 """
-function objective_value(::AbstractBenchmark, θ̄::AbstractArray, y::AbstractArray)
-    return dot(θ̄, y)
+function objective_value(::AbstractBenchmark, θ::AbstractArray, y::AbstractArray)
+    return dot(θ, y)
+end
+
+"""
+$TYPEDSIGNATURES
+
+Compute the objective value of the target in the sample (needs to exist).
+"""
+function objective_value(
+    bench::AbstractBenchmark, sample::DataSample{F,S,C,I}
+) where {F,S<:AbstractArray,C<:AbstractArray,I}
+    return objective_value(bench, sample.θ_true, sample.y_true)
+end
+
+"""
+$TYPEDSIGNATURES
+
+Compute the objective value of given solution `y`.
+"""
+function objective_value(
+    bench::AbstractBenchmark, sample::DataSample{F,S,C,I}, y::AbstractArray
+) where {F,S,C<:AbstractArray,I}
+    return objective_value(bench, sample.θ_true, y)
 end
 
 """
@@ -72,13 +114,11 @@ function compute_gap(
     res = 0.0
 
     for sample in dataset
+        target_obj = objective_value(bench, sample)
         x = sample.x
-        θ̄ = sample.θ_true
-        ȳ = sample.y_true
         θ = statistical_model(x)
-        y = maximizer(θ)
-        target_obj = objective_value(bench, θ̄, ȳ)
-        obj = objective_value(bench, θ̄, y)
+        y = maximizer(θ; maximizer_kwargs(bench, sample)...)
+        obj = objective_value(bench, sample, y)
         res += (target_obj - obj) / abs(target_obj)
     end
     return res / length(dataset)