def validate_message_dict(self, request_body):
<EOL>if isinstance(request_body, str):<EOL><INDENT>self.validate_message_text(request_body)<EOL><DEDENT>elif isinstance(request_body, dict):<EOL><INDENT>contents = request_body.get("<STR_LIT:content>", list())<EOL>for content in contents:<EOL><INDENT>if content is not None:<EOL><INDENT>if (content.get("<STR_LIT:type>") == "<STR_LIT>" or<EOL>isinstance(content.get("<STR_LIT:value>"), str)):<EOL><INDENT>message_text = content.get("<STR_LIT:value>", "<STR_LIT>")<EOL>self.validate_message_text(message_text)<EOL><DEDENT><DEDENT><DEDENT><DEDENT>
With the JSON dict that will be sent to SendGrid's API,
            check the content for SendGrid API keys - throw exception if found.

           :param request_body: The JSON dict that will be sent to SendGrid's
                                API.
           :type request_body: JSON serializable structure
           :raise ApiKeyIncludedException: If any content in request_body
                                           matches regex