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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

async def resolve_alias(cls, alias_key: str, etcd: etcd.AsyncEtcd):
        '''
        Resolve the tag using etcd so that the current instance indicates
        a concrete, latest image.

        Note that alias resolving does not take the registry component into
        account.
        '''
        alias_target = None
        repeats = 0
        while repeats < 8:
            prev_alias_key = alias_key
            alias_key = await etcd.get(f'images/_aliases/{alias_key}')
            if alias_key is None:
                alias_target = prev_alias_key
                break
            repeats += 1
        else:
            raise AliasResolutionFailed('Could not resolve the given image name!')
        known_registries = await get_known_registries(etcd)
        return cls(alias_target, known_registries)