def get_usr(self):
return conf.lib.clang_getCursorUSR(self)<EOL>
Return the Unified Symbol Resultion (USR) for the entity referenced
        by the given cursor (or None).

        A Unified Symbol Resolution (USR) is a string that identifies a
        particular entity (function, class, variable, etc.) within a
        program. USRs can be compared across translation units to determine,
        e.g., when references in one translation refer to an entity defined in
        another translation unit.