Django: adding cc in email with sengrid returns HTTP Error 400: Bad Request

I am following this link to send emails from Django using SendGrid. If my email address in cc and to_email is same, it returns HTTP Error 400: Bad Request. But it works fine if the email address is different. Did anyone solve this problem before? I need to add cc while sending an email from Django whether the email address is the same or different. Thanks in advance.

sg = SendGridAPIClient(development.EMAIL_HOST_PASSWORD)
cc_email = str(ImagingCenter.objects.get(institute_id=user.center_id).email)
from_email = development.DEFAULT_FROM_EMAIL
to_email = to_email
data = {
         "personalizations": [{
                        "to": [{
                            "email": to_email
                        }],
                        "cc": [
                            {
                                "email": cc_email
                            }
                        ],
                        "subject": "CC Email Testing"
                    }
                ],
                "from": {
                    "email": from_email
                },
                "content": [
                    {
                        "type": "text/html",
                        "value": html_message
                    }
                ]
            }
            response = sg.client.mail.send.post(request_body=data)