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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate_message_text(self, message_string):
 """With a message string, check to see if it contains a SendGrid API Key If a key is found, throw an exception :param message_string: message that will be sent :type message_string: string :raises ApiKeyIncludedException: If message_string matches a regex string """

        if isinstance(message_string, str):
            for regex in self.regexes:
                if regex.match(message_string) is not None:
                    raise ApiKeyIncludedException()