def filter_instance(self, inst, plist):
        """Remove properties from an instance that aren't in the PropertyList

        inst -- The pywbem.CIMInstance
        plist -- The property List, or None.  The list items must be all
            lowercase.

        """

        if plist is not None:
            for pname in inst.properties.keys():
                if pname.lower() not in plist and pname:
                    if inst.path is not None and pname in inst.path.keybindings:
                        continue
                    del inst.properties[pname]
Remove properties from an instance that aren't in the PropertyList

        inst -- The pywbem.CIMInstance
        plist -- The property List, or None.  The list items must be all
            lowercase.