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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_request(self, xml_request):
 """ Send the prepared XML request block to the CPS using the corect protocol. Args: xml_request -- A fully formed xml request string for the CPS. Returns: The raw xml response string. Raises: ConnectionError -- Can't establish a connection with the server. """

        if self._scheme == 'http':
            return self._send_http_request(xml_request)
        else:
            return self._send_socket_request(xml_request)