ld be a callable, which will be called with two tuples indicating the wheel version of this software and the wheel version in the file, if there is a discrepancy in the versions. This can be used to issue any warnings to raise any exceptions. If kwarg ``lib_only`` is True, only the purelib/platlib files are installed, and the headers, scripts, data and dist-info metadata are not written. If kwarg ``bytecode_hashed_invalidation`` is True, written bytecode will try to use file-hash based invalidation (PEP-552) on supported interpreter versions (CPython 3.7+). The return value is a :class:`InstalledDistribution` instance unless ``options.lib_only`` is True, in which case the return value is ``None``. Ú