4 files changed, 13 insertions, 14 deletions
diff --git a/lib/axlsx.rb b/lib/axlsx.rb
index 58096e7c..20af45e0 100644
--- a/lib/axlsx.rb
+++ b/lib/axlsx.rb
@@ -33,12 +33,8 @@ require 'bigdecimal'
 require 'set'
 require 'time'
 
-begin
-  if Gem.loaded_specs.has_key?("axlsx_styler")
-    raise StandardError, "Please remove `axlsx_styler` from your Gemfile, the associated functionality is now built-in to `caxlsx` directly."
-  end
-rescue StandardError
-  # Do nothing
+if Gem.loaded_specs.has_key?("axlsx_styler")
+  raise StandardError, "Please remove `axlsx_styler` from your Gemfile, the associated functionality is now built-in to `caxlsx` directly."
 end
 
 # xlsx generation with charts, images, automated column width, customizable styles
diff --git a/lib/axlsx/package.rb b/lib/axlsx/package.rb
index 2983ed72..20195ddc 100644
--- a/lib/axlsx/package.rb
+++ b/lib/axlsx/package.rb
@@ -330,11 +330,11 @@ module Axlsx
       end
       exts = workbook.images.map { |image| image.extname.downcase }
       exts.uniq.each do |ext|
-        ct = if ['jpeg', 'jpg'].include?(ext)
+        ct = if JPEG_EXS.include?(ext)
                JPEG_CT
-             elsif ext == 'gif'
+             elsif ext == GIF_EX
                GIF_CT
-             elsif ext == 'png'
+             elsif ext == PNG_EX
                PNG_CT
              end
         c_types << Axlsx::Default.new(:ContentType => ct, :Extension => ext)
diff --git a/lib/axlsx/util/constants.rb b/lib/axlsx/util/constants.rb
index 138c8bf0..459e0099 100644
--- a/lib/axlsx/util/constants.rb
+++ b/lib/axlsx/util/constants.rb
@@ -166,8 +166,8 @@ module Axlsx
   # xml content type extensions
   XML_EX = "xml"
 
-  # jpeg extension
-  JPEG_EX = "jpeg"
+  # jpeg extensions
+  JPEG_EXS = ["jpeg", "jpg"].freeze
 
   # gif extension
   GIF_EX = "gif"
diff --git a/lib/axlsx/workbook/worksheet/page_margins.rb b/lib/axlsx/workbook/worksheet/page_margins.rb
index 4d133c5a..9c2ddd8e 100644
--- a/lib/axlsx/workbook/worksheet/page_margins.rb
+++ b/lib/axlsx/workbook/worksheet/page_margins.rb
@@ -29,7 +29,10 @@ module Axlsx
       parse_options options
     end
 
-    serializable_attributes :left, :right, :bottom, :top, :header, :footer
+    # Possible margins to set
+    MARGIN_KEYS = [:left, :right, :top, :bottom, :header, :footer].freeze
+
+    serializable_attributes(*MARGIN_KEYS)
 
     # Default left and right margin (in inches)
     DEFAULT_LEFT_RIGHT = 0.75
@@ -65,10 +68,10 @@ module Axlsx
     attr_reader :footer
 
     # Set some or all margins at once.
-    # @param [Hash] margins the margins to set (possible keys are :left, :right, :top, :bottom, :header and :footer).
+    # @param [Hash] margins the margins to set. See {MARGIN_KEYS} for a list of possible keys.
     def set(margins)
       margins.select do |k, v|
-        next unless [:left, :right, :top, :bottom, :header, :footer].include? k
+        next unless MARGIN_KEYS.include? k
 
         send("#{k}=", v)
       end