'Returns a dict of changed fields with tz unaware datetimes.
Any timezone aware datetime field will be converted to UTC timezone
and returned as timezone unaware datetime.
This will allow us to pass these fields directly to a db update
method as they can\'t have timezone information.'

def cinder_obj_get_changes(self):

    changes = self.obj_get_changes()
    for (k, v) in changes.items():
        if (isinstance(v, datetime.datetime) and v.tzinfo):
            changes[k] = (v.replace(tzinfo=None) - v.utcoffset())
    return changes
