code: def get_s3_key(self):
          
          try:
              c = s3.connect_to_region(self._region,
                                       aws_access_key_id=self._aws_access_key_id,
                                       aws_secret_access_key=self._aws_secret_access_key)
              bucket = c.get_bucket(self._s3_bucket)
              key = bucket.get_key(self._s3_name)
              self._key_file = StringIO(unicode(key.get_contents_as_string().decode()))
              self._key_file.seek(0)
              key.close()
          except NoAuthHandlerFound:
              raise SergentSshException('Boto said that you should check your credentials')
          except S3ResponseError as e:
              logger.exception(e)
              raise SergentSshException('bucket %s or key %s not found' % (self._s3_bucket, self._s3_name))
docs: get ssh key in s3 bucket with specific name, load it in StringIO file
          :return: