'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.'

def get_usr(self):

    return conf.lib.clang_getCursorUSR(self)
