def install_variant(self, variant_resource, dry_run=False, overrides=None):
raise NotImplementedError<EOL>
Install a variant into this repository.

        Use this function to install a variant from some other package repository
        into this one.

        Args:
            variant_resource (`VariantResource`): Variant to install.
            dry_run (bool): If True, do not actually install the variant. In this
                mode, a `Variant` instance is only returned if the equivalent
                variant already exists in this repository; otherwise, None is
                returned.
            overrides (dict): Use this to change or add attributes to the
                installed variant. To remove attributes, set values to
                `PackageRepository.remove`.

        Returns:
            `VariantResource` object, which is the newly created variant in this
            repository. If `dry_run` is True, None may be returned.