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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 get_service_account_email(self, project=None):
 """Get the email address of the project's GCS service account :type project: str :param project: (Optional) Project ID to use for retreiving GCS service account email address. Defaults to the client's project. :rtype: str :returns: service account email address """

        if project is None:
            project = self.project
        path = "/projects/%s/serviceAccount" % (project,)
        api_response = self._base_connection.api_request(method="GET", path=path)
        return api_response["email_address"]