Add support for passing in cc list

sparkpost/transmissions.py

@@ -43,13 +43,20 @@ def _translate_keys(self, **kwargs):
         model['content']['html'] = kwargs.get('html')
         model['content']['text'] = kwargs.get('text')
         model['content']['template_id'] = kwargs.get('template')
-        model['content']['headers'] = kwargs.get('custom_headers')
+        model['content']['headers'] = kwargs.get('custom_headers', {})
 
         recipient_list = kwargs.get('recipient_list')
         if recipient_list:
             model['recipients']['list_id'] = recipient_list
         else:
             recipients = kwargs.get('recipients', [])
+            cc = kwargs.get('cc')
+            if cc and len(recipients) > 0:
+                model['content']['headers']['CC'] = ','.join(cc)
+                formatted_ccs = self._extractRecipients(cc)
+                for recipient in formatted_ccs:
+                    recipient['address'].update({'header_to': recipients[0]})
+                recipients = recipients + formatted_ccs
             model['recipients'] = self._extractRecipients(recipients)
 
         attachments = kwargs.get('attachments', [])

test/test_transmissions.py

@@ -49,6 +49,20 @@ def test_translate_keys_for_email_parsing():
     ]
 
 
+def test_translate_keys_with_cc():
+    t = Transmissions('uri', 'key')
+    results = t._translate_keys(recipients=['primary@example.com'],
+                                cc=['ccone@example.com'])
+    assert results['recipients'] == [
+        {'address': {'email': 'primary@example.com'}},
+        {'address': {'email': 'ccone@example.com',
+                     'header_to': 'primary@example.com'}},
+    ]
+    assert results['content']['headers'] == {
+        'CC': 'ccone@example.com'
+    }
+
+
 @responses.activate
 def test_success_send():
     responses.add(