diff --git a/lib/paapi.rb b/lib/paapi.rb
index 3228194..bee012d 100644
--- a/lib/paapi.rb
+++ b/lib/paapi.rb
@@ -1,81 +1,82 @@
-require 'paapi/version'
+require "paapi/version"
 
-require 'paapi/client'
-require 'paapi/item'
-require 'paapi/listing'
-require 'paapi/response'
+require "paapi/client"
+require "paapi/item"
+require "paapi/listing"
+require "paapi/response"
 
 module Paapi
   class Error < StandardError; end
+
   class NotImplemented < StandardError; end
   SEARCH_PARAMS = %i[Keywords Actor Artist Author Brand Title].freeze
-  DEFAULT_PARTNER_TYPE = 'Associates'
+  DEFAULT_PARTNER_TYPE = "Associates"
   DEFAULT_MARKET = :us
-  DEFAULT_CONDITION  = 'Any'
+  DEFAULT_CONDITION = "Any"
   DEFAULT_RESOURCES = [
-    'Images.Primary.Large',
-    'ItemInfo.ByLineInfo',
-    'ItemInfo.ContentInfo',
-    'ItemInfo.ExternalIds',
-    'ItemInfo.Features',
-    'ItemInfo.ManufactureInfo',
-    'ItemInfo.ProductInfo',
-    'ItemInfo.TechnicalInfo', # Includes format when Kindle
-    'ItemInfo.Title',
-    'ItemInfo.TradeInInfo',
-    'Offers.Listings.Availability.Message',
-    'Offers.Listings.Condition',
-    'Offers.Listings.Condition.SubCondition',
-    'Offers.Listings.DeliveryInfo.IsAmazonFulfilled',
-    'Offers.Listings.DeliveryInfo.IsFreeShippingEligible',
-    'Offers.Listings.DeliveryInfo.IsPrimeEligible',
-    'Offers.Listings.MerchantInfo',
-    'Offers.Listings.Price',
-    'Offers.Listings.SavingBasis'
+    "Images.Primary.Large",
+    "ItemInfo.ByLineInfo",
+    "ItemInfo.ContentInfo",
+    "ItemInfo.ExternalIds",
+    "ItemInfo.Features",
+    "ItemInfo.ManufactureInfo",
+    "ItemInfo.ProductInfo",
+    "ItemInfo.TechnicalInfo", # Includes format when Kindle
+    "ItemInfo.Title",
+    "ItemInfo.TradeInInfo",
+    "Offers.Listings.Availability.Message",
+    "Offers.Listings.Condition",
+    "Offers.Listings.Condition.SubCondition",
+    "Offers.Listings.DeliveryInfo.IsAmazonFulfilled",
+    "Offers.Listings.DeliveryInfo.IsFreeShippingEligible",
+    "Offers.Listings.DeliveryInfo.IsPrimeEligible",
+    "Offers.Listings.MerchantInfo",
+    "Offers.Listings.Price",
+    "Offers.Listings.SavingBasis"
   ].freeze
 
   Locale = Struct.new(:key, :name, :host, :region) do
     def site
-      host.sub('webservices', 'www')
+      host.sub("webservices", "www")
     end
   end
 
   MARKETPLACES = {
-    au: Locale.new(:au, 'Australia',	          'webservices.amazon.com.au', 'us-west-2'),
-    br: Locale.new(:br, 'Brazil',	              'webservices.amazon.com.br', 'us-east-1'),
-    ca: Locale.new(:ca, 'Canada',	              'webservices.amazon.ca',	   'us-east-1'),
-    fr: Locale.new(:fr, 'France',	              'webservices.amazon.fr',	   'eu-west-1'),
-    de: Locale.new(:de, 'Germany',	            'webservices.amazon.de',	   'eu-west-1'),
-    in: Locale.new(:in, 'India',	              'webservices.amazon.in',	   'eu-west-1'),
-    it: Locale.new(:it, 'Italy',	              'webservices.amazon.it',	   'eu-west-1'),
-    jp: Locale.new(:jp, 'Japan',	              'webservices.amazon.co.jp',	 'us-west-2'),
-    mx: Locale.new(:mx, 'Mexico',	              'webservices.amazon.com.mx', 'us-east-1'),
-    es: Locale.new(:es, 'Spain',                'webservices.amazon.es',	   'eu-west-1'),
-    tr: Locale.new(:tk, 'Turkey',	              'webservices.amazon.com.tr', 'eu-west-1'),
-    ae: Locale.new(:ae, 'United Arab Emirates',	'webservices.amazon.ae',	   'eu-west-1'),
-    uk: Locale.new(:uk, 'United Kingdom',	      'webservices.amazon.co.uk',	 'eu-west-1'),
-    us: Locale.new(:us, 'United States',	      'webservices.amazon.com',	   'us-east-1'),
+    au: Locale.new(:au, "Australia", "webservices.amazon.com.au", "us-west-2"),
+    br: Locale.new(:br, "Brazil", "webservices.amazon.com.br", "us-east-1"),
+    ca: Locale.new(:ca, "Canada", "webservices.amazon.ca", "us-east-1"),
+    fr: Locale.new(:fr, "France", "webservices.amazon.fr", "eu-west-1"),
+    de: Locale.new(:de, "Germany", "webservices.amazon.de", "eu-west-1"),
+    in: Locale.new(:in, "India", "webservices.amazon.in", "eu-west-1"),
+    it: Locale.new(:it, "Italy", "webservices.amazon.it", "eu-west-1"),
+    jp: Locale.new(:jp, "Japan", "webservices.amazon.co.jp", "us-west-2"),
+    mx: Locale.new(:mx, "Mexico", "webservices.amazon.com.mx", "us-east-1"),
+    es: Locale.new(:es, "Spain", "webservices.amazon.es", "eu-west-1"),
+    tr: Locale.new(:tk, "Turkey", "webservices.amazon.com.tr", "eu-west-1"),
+    ae: Locale.new(:ae, "United Arab Emirates",	"webservices.amazon.ae", "eu-west-1"),
+    uk: Locale.new(:uk, "United Kingdom", "webservices.amazon.co.uk", "eu-west-1"),
+    us: Locale.new(:us, "United States", "webservices.amazon.com", "us-east-1")
   }.freeze
 
-  Operation = Struct.new(:target_name, :endpoint_suffix, :http_method, :service )
+  Operation = Struct.new(:target_name, :endpoint_suffix, :http_method, :service)
 
   OPERATIONS = {
-    get_browse_nodes: Operation.new( 'GetBrowseNodes', 'getbrowsenodes', 'POST', 'ProductAdvertisingAPI' ),
-    get_items:        Operation.new( 'GetItems',       'getitems',       'POST', 'ProductAdvertisingAPI' ),
-    get_variations:   Operation.new( 'GetVariations',  'getvariations',  'POST', 'ProductAdvertisingAPI' ),
-    search_items:     Operation.new( 'SearchItems',    'searchitems',    'POST', 'ProductAdvertisingAPI' )
+    get_browse_nodes: Operation.new("GetBrowseNodes", "getbrowsenodes", "POST", "ProductAdvertisingAPI"),
+    get_items: Operation.new("GetItems", "getitems", "POST", "ProductAdvertisingAPI"),
+    get_variations: Operation.new("GetVariations", "getvariations", "POST", "ProductAdvertisingAPI"),
+    search_items: Operation.new("SearchItems", "searchitems", "POST", "ProductAdvertisingAPI")
   }.freeze
 
   class << self
     attr_accessor :access_key,
-                  :secret_key,
-                  :partner_tag,
-                  :partner_type,
-                  :market,
-                  :partner_market,
-                  :condition,
-                  :resources,
-                  :test_mode
+      :secret_key,
+      :partner_tag,
+      :partner_type,
+      :market,
+      :partner_market,
+      :condition,
+      :resources,
+      :test_mode
 
     def configure
       yield self
@@ -85,7 +86,6 @@ module Paapi
   end
 
   def symbolize_keys(hash)
-    Hash[hash.map{|k,v| v.is_a?(Hash) ? [k.to_sym, symbolize_keys(v)] : [k.to_sym, v] }]
+    hash.map { |k, v| v.is_a?(Hash) ? [k.to_sym, symbolize_keys(v)] : [k.to_sym, v] }.to_h
   end
 end
-