diff --git a/lib/desugaring.rb b/lib/desugaring.rb
index 8d52908..c0c3f5a 100644
--- a/lib/desugaring.rb
+++ b/lib/desugaring.rb
@@ -20,8 +20,10 @@ def all_the_sugar(recipients, event, message)
   #
   # Copy the contents of the previous method here and remove this sugar.
   #
-  def desugared_poetry(recipients, event, message)
-    implement_me!
+  def desugared_poetry recipients, event, message
+        mail message,
+      to: recipients.map(&:email),
+      subject: "You’re invited to #{event.title} on #{event.date}"
   end
 
   # Ruby allows you to pass arguments identified by name instead of just by position. They are really just
@@ -35,8 +37,9 @@ def desugared_poetry(recipients, event, message)
   #
   # Copy the contents of the previous method here and remove this sugar.
   #
-  def desugared_named_args(recipients, event, message)
-    implement_me!
+  def desugared_poetry recipients, event, message
+        mail message, {to: recipients.map(&:email),
+                       subject: "You’re invited to #{event.title} on #{event.date}"}
   end
 
   # Ruby’s general syntax for hashes is `{key => value, key => value, ...}`. Because it is so common to use
@@ -50,8 +53,9 @@ def desugared_named_args(recipients, event, message)
   #
   # Copy the contents of the previous method here and remove this sugar.
   #
-  def desugared_symbol_keys(recipients, event, message)
-    implement_me!
+  def desugared_poetry recipients, event, message
+        mail message, {:to => recipients.map(&:email),
+                       :subject => "You’re invited to #{event.title} on #{event.date}"}
   end
 
   # You may be wondering how `map(&:email)` works. When you precede the last argument of a method call with
@@ -69,8 +73,9 @@ def desugared_symbol_keys(recipients, event, message)
   #
   # Copy the contents of the previous method here and remove this sugar.
   #
-  def desugared_attr_proc(recipients, event, message)
-    implement_me!
+  def desugared_poetry recipients, event, message
+        mail message, {:to => recipients.map{|x| x.email},
+                       :subject => "You’re invited to #{event.title} on #{event.date}"}
   end
 
   # You may recall from the Ruby koans that when you put `#{something}` in a `"`-delimited string, Ruby will
@@ -87,8 +92,9 @@ def desugared_attr_proc(recipients, event, message)
   #
   # Copy the contents of the previous method here and remove this sugar.
   #
-  def desugared_interpolation(recipients, event, message)
-    implement_me!
+   def desugared_poetry recipients, event, message
+        mail message, {:to => recipients.map{|x| x.email},
+                       :subject => "You’re invited to " + (event.title).to_s + " on " + (event.date).to_s}
   end
 
   # Ruby tracks local variables lexically at compile time. Wherever you say `x = y`, the compiler assumes that
@@ -109,8 +115,9 @@ def desugared_interpolation(recipients, event, message)
   # Copy the contents of the previous method here and remove this sugar.
   # (Think: which names are local variables, and which are not?)
   #
-  def desugared_implicit_self(recipients, event, message)
-    implement_me!
+   def desugared_poetry recipients, event, message
+        self.mail message, {:to => recipients.map{|x| x.email},
+                       :subject => "You’re invited to " + (event.title).to_s + " on " + (event.date).to_s}
   end
 
   # In Ruby, unlike Python, there are no properties distinct from method calls. When you say `x.y`, you are
@@ -130,8 +137,9 @@ def desugared_implicit_self(recipients, event, message)
   # At this point, you should have code that looks remarkably like Javascript. Not _exactly_ like it,
   # but structurally quite similar!
   #
-  def desugared_implicit_parens(recipients, event, message)
-    implement_me!
+   def desugared_poetry recipients, event, message
+        self.mail(message, {:to => recipients.map{|x| x.email()},
+                       :subject => "You’re invited to " + (event.title()).to_s() + " on " + (event.date()).to_s()})
   end
 
   # In Ruby, every value is an object and every action is a method call. That includes operators. A binary
@@ -152,9 +160,12 @@ def desugared_implicit_parens(recipients, event, message)
   # P.P.P.S. For full credit on this one, note that addition is left-associative: the things on the left
   #   get added before the things on the right. (a + b + c) means ((a + b) + c), NOT (a + (b + c)).
   #
-  def desugared_operators(recipients, event, message)
-    implement_me!
-  end
+    def desugared_poetry recipients, event, message
+        self.mail(message,{:to => recipients.map{|x| x.email()},
+                           :subject => "You’re invited to ".+(   (event.title()).to_s().+(  " on ".+( (event.date()).to_s() )  )   )
+                          }
+                  )
+    end
 
   # Compare that to the version at the top.
   #
diff --git a/lib/retail_transaction.rb b/lib/retail_transaction.rb
index 1bfa0e3..545e1f0 100644
--- a/lib/retail_transaction.rb
+++ b/lib/retail_transaction.rb
@@ -39,6 +39,7 @@ def paid?
     state :processing_payment
     state :payment_declined
     state :settled
+    state :refunded
 
     event :check_out do
       transitions from: :ringing_up, to: :collecting_payment,
@@ -61,5 +62,9 @@ def paid?
     event :payment_declined do
       transitions from: :processing_payment, to: :payment_declined
     end
+
+    event :refund do
+      transitions from: :settled, to: :refunded
+    end
   end
 end
diff --git a/test/retail_transaction_test.rb b/test/retail_transaction_test.rb
index 823cbfe..72a327d 100644
--- a/test/retail_transaction_test.rb
+++ b/test/retail_transaction_test.rb
@@ -15,7 +15,7 @@
   end
 
   it "starts out empty" do
-    assert_equal true, tx.empty?
+    assert_equal true, tx.empty? 
   end
 
   it "cannot check out if no items" do
@@ -64,6 +64,11 @@
       assert_equal false, tx.collecting_payment?
       assert_equal true,  tx.processing_payment?
     end
+
+    it "cannot refund payment" do
+      assert_invalid_transition { tx.refund! }
+    end
+
   end
 
   describe "processing payment" do
@@ -103,6 +108,10 @@
       assert_equal false, tx.settled?
       assert_equal true,  tx.payment_declined?
     end
+
+    it "cannot be refunded" do
+      assert_invalid_transition { tx.refund! }
+    end
   end
 
   describe "with declined payment" do
@@ -152,5 +161,30 @@
     it "cannot be reopened" do
       assert_invalid_transition { tx.reopen! }
     end
+
+    it "can be refunded" do
+      tx.refund!
+      assert_equal false, tx.settled?
+      assert_equal true, tx.refunded?
+    end
+  end
+
+  describe "refunded purchase" do
+    before(:each) do
+      tx.add_item("bobcat")
+      tx.check_out!
+      tx.payment_info = "15 cents and a nail"
+      tx.process_payment!
+      tx.payment_authorized!
+      tx.refund!
+    end
+
+    it "cannot be refunded again" do 
+      assert_invalid_transition { tx.refund! }
+    end
+
+    it "cannot be reopened" do
+      assert_invalid_transition { tx.reopen! }
+    end
   end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index a343433..383ebf7 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -8,8 +8,8 @@
 
 # To see full test names when running tests:
 #
-# require "minitest/reporters"
-# Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
+require "minitest/reporters"
+Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 module Minitest::Assertions
   def assert_invalid_transition