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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 send(self, content_type='HTML'):
 """ Takes the recipients, body, and attachments of the Message and sends. Args: content_type: Can either be 'HTML' or 'Text', defaults to HTML. """


        payload = self.api_representation(content_type)

        endpoint = 'https://outlook.office.com/api/v1.0/me/sendmail'
        self._make_api_call('post', endpoint=endpoint, data=json.dumps(payload))