diff --git a/src/QUBODrivers.jl b/src/QUBODrivers.jl
index 317fe96..baac227 100644
--- a/src/QUBODrivers.jl
+++ b/src/QUBODrivers.jl
@@ -22,7 +22,6 @@ export MOI, Sample, SampleSet, Spin, ↓, ↑
 include("interface/sampler.jl")
 include("interface/attributes.jl")
 
-include("library/sampler/attributes.jl")
 include("library/sampler/wrappers/moi.jl")
 include("library/sampler/wrappers/qubotools.jl")
 
diff --git a/src/interface/sampler.jl b/src/interface/sampler.jl
index efaf469..525986f 100644
--- a/src/interface/sampler.jl
+++ b/src/interface/sampler.jl
@@ -10,8 +10,6 @@ function sample end
 
 function sample(::S) where {S<:AbstractSampler}
     error("`QUBODrivers.sample` is not implemented for '$S'")
-
-    return nothing
 end
 
 @doc raw"""
diff --git a/src/library/drivers/IdentitySampler.jl b/src/library/drivers/IdentitySampler.jl
index cc445c4..6580475 100644
--- a/src/library/drivers/IdentitySampler.jl
+++ b/src/library/drivers/IdentitySampler.jl
@@ -26,8 +26,6 @@ function sample_state(sampler::Optimizer{T}, n::Integer) where {T}
             v = QUBOTools.variable(sampler, i)
 
             error("Warm-start value for '$v' is missing")
-
-            return nothing
         end
     end
 
diff --git a/src/library/sampler/attributes.jl b/src/library/sampler/attributes.jl
deleted file mode 100644
index a2471df..0000000
--- a/src/library/sampler/attributes.jl
+++ /dev/null
@@ -1,8 +0,0 @@
-const MOI_ATTRIBUTE = Union{
-    MOI.Name,
-    MOI.Silent,
-    MOI.TimeLimitSec,
-    MOI.NumberOfThreads,
-    MOI.VariablePrimalStart,
-}
-
diff --git a/src/library/sampler/wrappers/moi.jl b/src/library/sampler/wrappers/moi.jl
index 73cb37b..67cbd59 100644
--- a/src/library/sampler/wrappers/moi.jl
+++ b/src/library/sampler/wrappers/moi.jl
@@ -6,27 +6,16 @@ MOI.supports_constraint(
 ) = false
 
 # ~ They are also binary
-MOI.supports_constraint(
-    ::AbstractSampler,
-    ::Type{VI},
-    ::Type{MOI.ZeroOne},
-) = true
+MOI.supports_constraint(::AbstractSampler, ::Type{VI}, ::Type{MOI.ZeroOne}) = true
 
-MOI.supports_constraint(
-    ::AbstractSampler,
-    ::Type{VI},
-    ::Type{Spin},
-) = true
+MOI.supports_constraint(::AbstractSampler, ::Type{VI}, ::Type{Spin}) = true
 
 # ~ Objective Function Support
-MOI.supports(
-    ::AbstractSampler,
-    ::MOI.ObjectiveFunction{<:Any}
-) = false
+MOI.supports(::AbstractSampler, ::MOI.ObjectiveFunction{<:Any}) = false
 
 MOI.supports(
     ::AbstractSampler{T},
-    ::MOI.ObjectiveFunction{<:Union{SQF{T}, SAF{T}, VI}}
+    ::MOI.ObjectiveFunction{<:Union{SQF{T},SAF{T},VI}},
 ) where {T} = true
 
 # By default, all samplers are their own raw solvers.
@@ -144,12 +133,8 @@ function MOI.get(sampler::AbstractSampler{T}, vp::MOI.VariablePrimal, vi::VI) wh
 
     if isempty(ω)
         error("Invalid result index '$i'; There are no solutions")
-
-        return nothing
     elseif !(1 <= i <= m)
         error("Invalid result index '$i'; There are $(m) solutions")
-
-        return nothing
     end
 
     j = QUBOTools.index(sampler, vi)
@@ -161,49 +146,3 @@ end
 function MOI.get(sampler::AbstractSampler, ::MOI.NumberOfVariables)
     return QUBOTools.dimension(sampler)
 end
-
-# ~*~ File IO: Base API ~*~ #
-# function Base.write(
-#     filename::AbstractString,
-#     sampler::AbstractSampler,
-#     fmt::QUBOTools.AbstractFormat = QUBOTools.infer_format(filename),
-# )
-#     return QUBOTools.write_model(filename, sampler, fmt)
-# end
-
-# function Base.read!(
-#     filename::AbstractString,
-#     sampler::AbstractSampler,
-#     fmt::QUBOTools.AbstractFormat = QUBOTools.infer_format(filename),
-# )
-#     sampler.source = QUBOTools.read_model(filename, fmt)
-#     sampler.target = QUBOTools.format(sampler, sampler.source)
-
-#     return sampler
-# end
-
-function warm_start(sampler::AbstractSampler, i::Integer)
-    v = QUBOTools.variable_inv(sampler, i)
-    x = MOI.get(sampler, MOI.VariablePrimalStart(), v)
-
-    if isnothing(x)
-        return nothing
-    else
-        return QUBOTools.cast(
-            source_domain(sampler) => target_domain(sampler),
-            round(Int, x),
-        )
-    end
-end
-
-function warm_start(sampler::AbstractSampler{T}) where {T}
-    n = MOI.get(sampler, MOI.NumberOfVariables())
-    s = sizehint!(Dict{Int,Int}(), n)
-
-    for i = 1:n
-        x = warm_start(sampler, i)
-        isnothing(x) || (s[i] = x)
-    end
-
-    return s
-end
diff --git a/src/library/setup/error.jl b/src/library/setup/error.jl
index 7075e28..bb7e6f5 100644
--- a/src/library/setup/error.jl
+++ b/src/library/setup/error.jl
@@ -10,6 +10,4 @@ end
 
 function setup_error(msg::AbstractString)
     throw(DriverSetupError(msg))
-
-    return nothing
 end
diff --git a/src/library/setup/parse.jl b/src/library/setup/parse.jl
index 6cf5b25..8e4a01b 100644
--- a/src/library/setup/parse.jl
+++ b/src/library/setup/parse.jl
@@ -4,8 +4,6 @@ end
 
 function __setup_parse(args...)
     setup_error("Macro takes 1 or 2 arguments, not '$(length(args))'")
-
-    return nothing
 end
 
 function __setup_parse(expr)
@@ -17,16 +15,12 @@ function __setup_parse(expr)
         setup_error(
             "Single argument must be either an identifier or a `begin ... end` block",
         )
-
-        return nothing
     end
 end
 
 function __setup_parse(id, block)
     if !(id isa Symbol) || !Base.isidentifier(id)
         setup_error("First argument must be a valid identifier")
-
-        return nothing
     end
 
     if !(block isa Expr && block.head === :block)
@@ -55,32 +49,24 @@ function __setup_parse_block(block; id = :Optimizer)
                 if key === :name
                     if !isnothing(name)
                         setup_error("Duplicate entries for 'name'")
-
-                        return nothing
                     end
 
                     name = value
                 elseif key === :version
                     if !isnothing(version)
                         setup_error("Duplicate entries for 'version'")
-
-                        return nothing
                     end
 
                     version = value
                 elseif key === :attributes
                     if !isnothing(attributes)
                         setup_error("Duplicate entries for 'attributes' block")
-
-                        return nothing
                     end
 
                     if !(value isa Expr && value.head === :block)
                         setup_error(
                             "Sampler attributes must be placed inside a `begin ... end` block",
                         )
-
-                        return nothing
                     end
 
                     attributes = _AttrSpec[]
@@ -96,25 +82,17 @@ function __setup_parse_block(block; id = :Optimizer)
                     setup_error(
                         "Sampler configuration keys must be either 'name', 'version' or 'attributes', not '$key'",
                     )
-
-                    return nothing
                 end
             else
                 setup_error("Sampler configuration keys must be a valid identifiers")
-
-                return nothing
             end
         else
             setup_error("Sampler configuration must be provided by `key = value` pairs")
-
-            return nothing
         end
     end
 
     if isnothing(name)
         setup_error("'name' entry is missing")
-
-        return nothing
     end
 
     if isnothing(version)
@@ -149,16 +127,12 @@ function __setup_parse_attr(stmt)
     if attr isa Symbol # ~ MOI attribute only
         if !(Base.isidentifier(attr))
             setup_error("Attribute identifier '$attr' is not valid")
-
-            return nothing
         end
 
         opt_attr = attr
     elseif attr isa String # ~ Raw attribute only
         if isempty(attr)
             setup_error("Raw attribute key can't be an empty string")
-
-            return nothing
         end
 
         raw_attr = attr
@@ -168,8 +142,6 @@ function __setup_parse_attr(stmt)
         if attr isa Symbol
             if !(Base.isidentifier(attr))
                 setup_error("Attribute identifier '$attr' is not a valid one")
-
-                return nothing
             end
 
             opt_attr = attr
@@ -181,18 +153,12 @@ function __setup_parse_attr(stmt)
             if opt_attr isa Symbol && raw_attr isa String
                 if !(Base.isidentifier(opt_attr))
                     setup_error("Attribute identifier '$opt_attr' is not a valid one")
-
-                    return nothing
                 end
             else
                 setup_error("Invalid attribute identifier '$name($raw)'")
-
-                return nothing
             end
         else
             setup_error("Invalid attribute identifier '$attr'")
-
-            return nothing
         end
     elseif attr isa Expr && (attr.head === :ref || attr.head === :call)
         opt_attr, raw_attr = attr.args
@@ -200,18 +166,12 @@ function __setup_parse_attr(stmt)
         if opt_attr isa Symbol && raw_attr isa String
             if !(Base.isidentifier(opt_attr))
                 setup_error("Attribute identifier '$opt_attr' is not a valid one")
-
-                return nothing
             end
         else
             setup_error("Invalid attribute identifier '$name[$raw_attr]'")
-
-            return nothing
         end
     else
         setup_error("Invalid attribute signature '$attr'")
-
-        return nothing
     end
 
     if !isnothing(raw_attr)
diff --git a/src/library/setup/quote.jl b/src/library/setup/quote.jl
index daeb4ae..bb4886e 100644
--- a/src/library/setup/quote.jl
+++ b/src/library/setup/quote.jl
@@ -236,27 +236,19 @@ function __setup_quote_moi_attrs(spec::_SamplerSpec)
         function MOI.set(sampler::$(Optimizer){T}, ::MOI.VariablePrimalStart, vi::VI, value) where {T}
             if !(isnothing(value) || value isa Real)
                 error("Value for 'MOI.VariablePrimalStart' must be an integer, or 'nothing'")
-
-                return nothing
             end
 
             if !isnothing(value)
                 if !(value isa Real && isinteger(value))
                     error("Value for 'MOI.VariablePrimalStart' must be an integer, or 'nothing'")
-
-                    return nothing
                 end
 
                 X = QUBOTools.domain(sampler)
 
                 if X === QUBOTools.BoolDomain && !(value == zero(value) || value == one(value))
                     error("Integer value for 'MOI.VariablePrimalStart' must be either '0' or '1'")
-
-                    return nothing
                 elseif X === QUBOTools.SpinDomain && !(value == -one(value) || value == one(value))
                     error("Integer value for 'MOI.VariablePrimalStart' must be either '-1' or '1'")
-
-                    return nothing
                 end
             end