Allow the __str__ method for the Mail object return an String instead of a NoneType

Author: diegoc-am

sendgrid/helpers/mail/mail.py

@@ -33,7 +33,7 @@ def __init__(
             self.add_content(content)
 
     def __str__(self):
-        self.get()
+        return str(self.get())
 
     def get(self):
         """

test/test_mail.py

@@ -65,6 +65,8 @@ def test_helloEmail(self):
             '"subject": "Hello World from the SendGrid Python Library"}'
         )
 
+        self.assertTrue(isinstance(str(mail), str))
+
     def test_kitchenSink(self):
         self.maxDiff = None