'Retrieve hypervisor system information.
:rtype: ``dict``'

def ex_get_hypervisor_sysinfo(self):

    xml = self.connection.getSysinfo()
    etree = ET.XML(xml)
    attributes = ['bios', 'system', 'processor', 'memory_device']
    sysinfo = {}
    for attribute in attributes:
        element = etree.find(attribute)
        entries = self._get_entries(element=element)
        sysinfo[attribute] = entries
    return sysinfo
