backend
:param _allow_fallback:
    Whether to allow the fallback to building a wheel and extracting
    the metadata from it. Should be passed as a keyword argument only.

:returns: Name of the newly created subfolder within
          ``metadata_directory``, containing the metadata.

.. admonition:: Fallback

    If the build backend does not define a hook with this name and
    ``_allow_fallback`` is truthy, the backend will be asked to build a
    wheel via the ``build_wheel`` hook and the dist-info extracted from
    that will be returned.
Ú prepare_metadata_for_build_wheelr¤