diff --git a/sendgrid/helpers/mail/mail.py b/sendgrid/helpers/mail/mail.py
index ce8bb2f0c..db2399310 100644
--- a/sendgrid/helpers/mail/mail.py
+++ b/sendgrid/helpers/mail/mail.py
@@ -256,9 +256,9 @@ def add_to(
                     email = To(email, None)
                 elif isinstance(email, tuple):
                     email = To(email[0], email[1])
-                elif not isinstance(email, To):
+                elif not isinstance(email, Email):
                     raise ValueError(
-                        'Please use a tuple, To, or a str for a to_email list.'
+                        'Please use a To/Cc/Bcc, tuple, or a str for a to_email list.'
                     )
                 self._set_emails(email, global_substitutions, is_multiple, p)
         else:
diff --git a/test/test_mail_helpers.py b/test/test_mail_helpers.py
index dff3de5b2..202d3948b 100644
--- a/test/test_mail_helpers.py
+++ b/test/test_mail_helpers.py
@@ -14,7 +14,7 @@
     ClickTracking, Content,
     DynamicTemplateData, Email, From,
     Mail, Personalization,
-    Subject, Substitution, To, TrackingSettings
+    Subject, Substitution, To, Cc, Bcc, TrackingSettings
 )
 
 
@@ -310,68 +310,74 @@ def test_error_is_not_raised_on_to_emails_set_to_list_of_tuples(self):
             ('test+to1@example.com', 'Example To Name 1')
         ]
 
-        try:
-            Mail(
-                from_email=From('test+from@example.com', 'Example From Name'),
-                to_emails=to_emails,
-                subject=Subject('Sending with SendGrid is Fun'),
-                plain_text_content=PlainTextContent(
-                    'and easy to do anywhere, even with Python'),
-                html_content=HtmlContent(
-                    '<strong>and easy to do anywhere, even with Python</strong>'))
-        except:
-            self.fail('Mail() raised an error on list of tuples')
+        Mail(
+            from_email=From('test+from@example.com', 'Example From Name'),
+            to_emails=to_emails,
+            subject=Subject('Sending with SendGrid is Fun'),
+            plain_text_content=PlainTextContent(
+                'and easy to do anywhere, even with Python'),
+            html_content=HtmlContent(
+                '<strong>and easy to do anywhere, even with Python</strong>'))
 
     def test_error_is_not_raised_on_to_emails_set_to_list_of_strs(self):
         from sendgrid.helpers.mail import (PlainTextContent, HtmlContent)
         self.maxDiff = None
         to_emails = ['test+to0@example.com', 'test+to1@example.com']
 
-        try:
-            Mail(
-                from_email=From('test+from@example.com', 'Example From Name'),
-                to_emails=to_emails,
-                subject=Subject('Sending with SendGrid is Fun'),
-                plain_text_content=PlainTextContent(
-                    'and easy to do anywhere, even with Python'),
-                html_content=HtmlContent(
-                    '<strong>and easy to do anywhere, even with Python</strong>'))
-        except:
-            self.fail('Mail() raised an error on list of strings')
+        Mail(
+            from_email=From('test+from@example.com', 'Example From Name'),
+            to_emails=to_emails,
+            subject=Subject('Sending with SendGrid is Fun'),
+            plain_text_content=PlainTextContent(
+                'and easy to do anywhere, even with Python'),
+            html_content=HtmlContent(
+                '<strong>and easy to do anywhere, even with Python</strong>'))
 
     def test_error_is_not_raised_on_to_emails_set_to_a_str(self):
         from sendgrid.helpers.mail import (PlainTextContent, HtmlContent)
         self.maxDiff = None
         to_emails = 'test+to0@example.com'
 
-        try:
-            Mail(
-                from_email=From('test+from@example.com', 'Example From Name'),
-                to_emails=to_emails,
-                subject=Subject('Sending with SendGrid is Fun'),
-                plain_text_content=PlainTextContent(
-                    'and easy to do anywhere, even with Python'),
-                html_content=HtmlContent(
-                    '<strong>and easy to do anywhere, even with Python</strong>'))
-        except:
-            self.fail('Mail() raised an error on a string')
+        Mail(
+            from_email=From('test+from@example.com', 'Example From Name'),
+            to_emails=to_emails,
+            subject=Subject('Sending with SendGrid is Fun'),
+            plain_text_content=PlainTextContent(
+                'and easy to do anywhere, even with Python'),
+            html_content=HtmlContent(
+                '<strong>and easy to do anywhere, even with Python</strong>'))
 
     def test_error_is_not_raised_on_to_emails_set_to_a_tuple(self):
         from sendgrid.helpers.mail import (PlainTextContent, HtmlContent)
         self.maxDiff = None
         to_emails = ('test+to0@example.com', 'Example To Name 0')
 
-        try:
-            Mail(
-                from_email=From('test+from@example.com', 'Example From Name'),
-                to_emails=to_emails,
-                subject=Subject('Sending with SendGrid is Fun'),
-                plain_text_content=PlainTextContent(
-                    'and easy to do anywhere, even with Python'),
-                html_content=HtmlContent(
-                    '<strong>and easy to do anywhere, even with Python</strong>'))
-        except:
-            self.fail('Mail() raised an error on a tuple of strings')
+        Mail(
+            from_email=From('test+from@example.com', 'Example From Name'),
+            to_emails=to_emails,
+            subject=Subject('Sending with SendGrid is Fun'),
+            plain_text_content=PlainTextContent(
+                'and easy to do anywhere, even with Python'),
+            html_content=HtmlContent(
+                '<strong>and easy to do anywhere, even with Python</strong>'))
+
+    def test_error_is_not_raised_on_to_emails_includes_bcc_cc(self):
+        from sendgrid.helpers.mail import (PlainTextContent, HtmlContent)
+        self.maxDiff = None
+        to_emails = [
+            To('test+to0@example.com', 'Example To Name 0'),
+            Bcc('test+bcc@example.com', 'Example Bcc Name 1'),
+            Cc('test+cc@example.com', 'Example Cc Name 2')
+        ]
+
+        Mail(
+            from_email=From('test+from@example.com', 'Example From Name'),
+            to_emails=to_emails,
+            subject=Subject('Sending with SendGrid is Fun'),
+            plain_text_content=PlainTextContent(
+                'and easy to do anywhere, even with Python'),
+            html_content=HtmlContent(
+                '<strong>and easy to do anywhere, even with Python</strong>'))
 
     def test_dynamic_template_data(self):
         self.maxDiff = None