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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 upload(self, src_file_path, dst_file_name=None):
 """Upload the specified file to the server."""

        self._check_session()
        status, data = self._rest.upload_file(
            'files', src_file_path, dst_file_name)
        return data