diff --git a/lib/options_model/base.rb b/lib/options_model/base.rb
index 02a06e2..7249413 100644
--- a/lib/options_model/base.rb
+++ b/lib/options_model/base.rb
@@ -10,9 +10,7 @@ class Base
     validate do
       self.class.attribute_names.each do |attribute_name|
         attribute = public_send(attribute_name)
-        if attribute.is_a?(self.class) && attribute.invalid?
-          errors.add attribute_name, :invalid
-        end
+        errors.add attribute_name, :invalid if attribute.is_a?(self.class) && attribute.invalid?
       end
     end
 
@@ -22,14 +20,14 @@ def ==(other)
         nested_attributes == other.nested_attributes &&
         unused_attributes == other.unused_attributes
     end
-    alias :eql? :==
+    alias eql? ==
 
     def hash
       [attributes, nested_attributes, unused_attributes].hash
     end
 
     def inspect
-      "#<#{self.class.name}:OptionsModel #{self.to_h}>"
+      "#<#{self.class.name}:OptionsModel #{to_h}>"
     end
 
     def self.inspect
diff --git a/lib/options_model/concerns/attribute_assignment.rb b/lib/options_model/concerns/attribute_assignment.rb
index 380c246..041badf 100644
--- a/lib/options_model/concerns/attribute_assignment.rb
+++ b/lib/options_model/concerns/attribute_assignment.rb
@@ -18,9 +18,7 @@ def initialize_dup(other)
       def update(other)
         return unless other
 
-        unless other.respond_to?(:to_h)
-          raise ArgumentError, "#{other} must be respond to `to_h`"
-        end
+        raise ArgumentError, "#{other} must be respond to `to_h`" unless other.respond_to?(:to_h)
 
         other.to_h.each do |k, v|
           if respond_to?("#{k}=")
@@ -47,9 +45,7 @@ def []=(key, val)
       end
 
       def fetch(key, default = nil)
-        if self.class.attribute_names.exclude?(key.to_sym) && default.nil? && !block_given?
-          raise KeyError, "attribute not found"
-        end
+        raise KeyError, "attribute not found" if self.class.attribute_names.exclude?(key.to_sym) && default.nil? && !block_given?
 
         value = respond_to?(key) ? public_send(key) : nil
         return value if value
diff --git a/lib/options_model/concerns/attributes.rb b/lib/options_model/concerns/attributes.rb
index 948064a..1cd7aa1 100644
--- a/lib/options_model/concerns/attributes.rb
+++ b/lib/options_model/concerns/attributes.rb
@@ -16,10 +16,9 @@ def attribute(name, cast_type, default: nil, array: false)
 
           attribute_defaults[name] = default
           default_extractor =
-            case
-            when default.respond_to?(:call)
+            if default.respond_to?(:call)
               ".call"
-            when default.duplicable?
+            elsif default.duplicable?
               ".deep_dup"
             else
               ""
@@ -55,13 +54,11 @@ def #{name}=(value)
               end
               STR
 
-              if cast_type == :boolean
-                generated_attribute_methods.send :alias_method, :"#{name}?", name
-              end
+              generated_attribute_methods.send :alias_method, :"#{name}?", name if cast_type == :boolean
             end
           end
 
-          self.attribute_names_for_inlining << name
+          attribute_names_for_inlining << name
 
           self
         end
@@ -69,9 +66,8 @@ def #{name}=(value)
         def enum_attribute(name, enum, default: nil, allow_nil: false)
           check_not_finalized!
 
-          unless enum.is_a?(Array) && enum.any?
-            raise ArgumentError, "enum should be an Array and can't empty"
-          end
+          raise ArgumentError, "enum should be an Array and can't empty" unless enum.is_a?(Array) && enum.any?
+
           enum = enum.map(&:to_s)
 
           attribute name, :string, default: default
@@ -80,11 +76,11 @@ def enum_attribute(name, enum, default: nil, allow_nil: false)
           generated_class_methods.synchronize do
             generated_class_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
             def #{pluralized_name}
-              %w(#{enum.join(" ")}).freeze
+              %w(#{enum.join(' ')}).freeze
             end
             STR
 
-            validates name, inclusion: {in: enum}, allow_nil: allow_nil
+            validates name, inclusion: { in: enum }, allow_nil: allow_nil
           end
 
           self
@@ -93,17 +89,15 @@ def #{pluralized_name}
         def embeds_one(name, class_name: nil, anonymous_class: nil)
           check_not_finalized!
 
-          if class_name.blank? && anonymous_class.nil?
-            raise ArgumentError, "must provide at least one of `class_name` or `anonymous_class`"
-          end
+          raise ArgumentError, "must provide at least one of `class_name` or `anonymous_class`" if class_name.blank? && anonymous_class.nil?
 
           name = name.to_sym
           check_name_validity! name
 
-          if class_name.present?
-            nested_classes[name] = class_name.constantize
+          nested_classes[name] = if class_name.present?
+            class_name.constantize
           else
-            nested_classes[name] = anonymous_class
+            anonymous_class
           end
 
           generated_attribute_methods.synchronize do
@@ -130,7 +124,7 @@ def #{name}=(value)
             STR
           end
 
-          self.attribute_names_for_nesting << name
+          attribute_names_for_nesting << name
 
           self
         end
@@ -160,60 +154,56 @@ def finalized?
         end
 
         def finalize!(nested = true)
-          if nested
-            nested_classes.values.each(&:finalize!)
-          end
+          nested_classes.values.each(&:finalize!) if nested
 
           @finalized = true
         end
 
         protected
 
-        def check_name_validity!(symbolized_name)
-          if dangerous_attribute_method?(symbolized_name)
-            raise ArgumentError, "#{symbolized_name} is defined by #{OptionsModel::Base}. Check to make sure that you don't have an attribute or method with the same name."
-          end
+          def check_name_validity!(symbolized_name)
+            if dangerous_attribute_method?(symbolized_name)
+              raise ArgumentError, "#{symbolized_name} is defined by #{OptionsModel::Base}. Check to make sure that you don't have an attribute or method with the same name."
+            end
 
-          if attribute_names_for_inlining.include?(symbolized_name) || attribute_names_for_nesting.include?(symbolized_name)
-            raise ArgumentError, "duplicate define attribute `#{symbolized_name}`"
+            if attribute_names_for_inlining.include?(symbolized_name) || attribute_names_for_nesting.include?(symbolized_name)
+              raise ArgumentError, "duplicate define attribute `#{symbolized_name}`"
+            end
           end
-        end
 
-        def check_not_finalized!
-          if finalized?
-            raise "can't modify finalized #{self}"
+          def check_not_finalized!
+            raise "can't modify finalized #{self}" if finalized?
           end
-        end
 
-        # A method name is 'dangerous' if it is already (re)defined by OptionsModel, but
-        # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
-        def dangerous_attribute_method?(name) # :nodoc:
-          method_defined_within?(name, OptionsModel::Base)
-        end
+          # A method name is 'dangerous' if it is already (re)defined by OptionsModel, but
+          # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
+          def dangerous_attribute_method?(name) # :nodoc:
+            method_defined_within?(name, OptionsModel::Base)
+          end
 
-        def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
-          if klass.method_defined?(name) || klass.private_method_defined?(name)
-            if superklass.method_defined?(name) || superklass.private_method_defined?(name)
-              klass.instance_method(name).owner != superklass.instance_method(name).owner
+          def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc:
+            if klass.method_defined?(name) || klass.private_method_defined?(name)
+              if superklass.method_defined?(name) || superklass.private_method_defined?(name)
+                klass.instance_method(name).owner != superklass.instance_method(name).owner
+              else
+                true
+              end
             else
-              true
+              false
             end
-          else
-            false
           end
-        end
 
-        def generated_attribute_methods
-          @generated_attribute_methods ||= Module.new {
-            extend Mutex_m
-          }.tap { |mod| include mod }
-        end
+          def generated_attribute_methods
+            @generated_attribute_methods ||= Module.new do
+              extend Mutex_m
+            end.tap { |mod| include mod }
+          end
 
-        def generated_class_methods
-          @generated_class_methods ||= Module.new {
-            extend Mutex_m
-          }.tap { |mod| extend mod }
-        end
+          def generated_class_methods
+            @generated_class_methods ||= Module.new do
+              extend Mutex_m
+            end.tap { |mod| extend mod }
+          end
       end
     end
   end
diff --git a/lib/options_model/concerns/serialization.rb b/lib/options_model/concerns/serialization.rb
index 781397a..940ed65 100644
--- a/lib/options_model/concerns/serialization.rb
+++ b/lib/options_model/concerns/serialization.rb
@@ -35,7 +35,7 @@ def load(yaml)
           return new unless yaml
           return new unless yaml.is_a?(String) && /^---/.match?(yaml)
 
-          hash = YAML.load(yaml) || Hash.new
+          hash = YAML.safe_load(yaml) || {}
 
           unless hash.is_a? Hash
             raise ArgumentError,
diff --git a/options_model.gemspec b/options_model.gemspec
index 09be78a..c6b0502 100644
--- a/options_model.gemspec
+++ b/options_model.gemspec
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-$:.push File.expand_path("../lib", __FILE__)
+$LOAD_PATH.push File.expand_path("lib", __dir__)
 
 # Maintain your gem's version:
 require "options_model/version"
diff --git a/test/dummy/config/environments/production.rb b/test/dummy/config/environments/production.rb
index 78d2f09..cd5d399 100644
--- a/test/dummy/config/environments/production.rb
+++ b/test/dummy/config/environments/production.rb
@@ -45,7 +45,7 @@
   config.log_level = :debug
 
   # Prepend all log lines with the following tags.
-  config.log_tags = [ :request_id ]
+  config.log_tags = [:request_id]
 
   # Use a different cache store in production.
   # config.cache_store = :mem_cache_store
diff --git a/test/dummy/config/spring.rb b/test/dummy/config/spring.rb
index ff5ba06..c5933e4 100644
--- a/test/dummy/config/spring.rb
+++ b/test/dummy/config/spring.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-%w(
+%w[
   .ruby-version
   .rbenv-vars
   tmp/restart.txt
   tmp/caching-dev.txt
-).each { |path| Spring.watch(path) }
+].each { |path| Spring.watch(path) }
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 078c5a9..f333899 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require File.expand_path("../../test/dummy/config/environment.rb", __FILE__)
+require File.expand_path("../test/dummy/config/environment.rb", __dir__)
 require "rails/test_help"
 
 # Filter out Minitest backtrace while allowing backtrace from other libraries
@@ -11,7 +11,7 @@
 
 # Load fixtures from the engine
 if ActiveSupport::TestCase.respond_to?(:fixture_path=)
-  ActiveSupport::TestCase.fixture_path = File.expand_path("../fixtures", __FILE__)
+  ActiveSupport::TestCase.fixture_path = File.expand_path("fixtures", __dir__)
   ActionDispatch::IntegrationTest.fixture_path = ActiveSupport::TestCase.fixture_path
   ActiveSupport::TestCase.file_fixture_path = ActiveSupport::TestCase.fixture_path + "/files"
   ActiveSupport::TestCase.fixtures :all