'Add storage to the node
:param  node: The server to add storage to
:type   node: :class:`Node`
:param  amount: The amount of storage to add, in GB
:type   amount: ``int``
:param  speed: The disk speed type
:type   speed: ``str``
:param  scsi_id: The target SCSI ID (optional)
:type   scsi_id: ``int``
:rtype: ``bool``'

def ex_add_storage_to_node(self, node, amount, speed='STANDARD', scsi_id=None):

    update_node = ET.Element('addDisk', {'xmlns': TYPES_URN})
    update_node.set('id', node.id)
    ET.SubElement(update_node, 'sizeGb').text = str(amount)
    ET.SubElement(update_node, 'speed').text = speed.upper()
    if (scsi_id is not None):
        ET.SubElement(update_node, 'scsiId').text = str(scsi_id)
    result = self.connection.request_with_orgId_api_2('server/addDisk', method='POST', data=ET.tostring(update_node)).object
    response_code = findtext(result, 'responseCode', TYPES_URN)
    return (response_code in ['IN_PROGRESS', 'OK'])
