Simplify .find and optimize its usage

lib/classy_enum/base.rb

@@ -57,12 +57,10 @@ def inherited(klass)
       #  Priority.build(:low) # => Priority::Low.new
       #  Priority.build(:invalid_option) # => :invalid_option
       def build(value, options={})
-        return value if value.blank? && options[:allow_blank]
+        object = find(value)
 
-        # Return the value if it is not a valid member
-        return value unless all.map(&:to_s).include? value.to_s
+        return value if object.nil? || (options[:allow_blank] && object.nil?)
 
-        object = "#{base_class}::#{value.to_s.camelize}".constantize.new
         object.owner = options[:owner]
         object.serialize_as_json = options[:serialize_as_json]
         object.allow_blank = options[:allow_blank]

lib/classy_enum/collection.rb

@@ -83,11 +83,11 @@ def each
       #  Priority.find('high') # => Priority::High.new
       #  Priority.find {|e| e.to_sym == :high } # => Priority::High.new
       def find(key=nil)
-        return super if block_given?
-
-        key = build(key)
-        return nil unless key.is_a?(ClassyEnum::Base)
-        super { |e| e == key }
+        if block_given?
+          super
+        elsif map(&:to_s).include? key.to_s
+          super { |e| e.to_s == key.to_s }
+        end
       end
 
       alias detect find