def find_eggs_for_plat_repo(brood_client, plat_repo):
    """ Find the unique eggs for a given platform repository. Some eggs are
    listed in multiple indexed python tags, so we want to ensure that each
    egg is only referenced once to prevent duplication.

    Parameters
    ----------

    brood_client: BroodClient
        hatcher.core.brood_client.BroodClient instance

    plat_repo: SinglePlatformRepository
        hatcher.core.v*.repository.SinglePlatformRepository instance

    Returns
    -------
    dict: Containing egg metadata indexed by sha256

    """
    eggs_dict = {}
    for python_tag in sorted(brood_client.list_python_tags()):
        egg_index = plat_repo.egg_index(python_tag)
        for _, index_entry in egg_index.items():
            metadata = plat_repo.egg_metadata(python_tag, index_entry[
                'name'], '-'.join([str(index_entry['version']), str(
                index_entry['build'])]))
            sha256_key = metadata['sha256']
            if sha256_key not in eggs_dict:
                eggs_dict[sha256_key] = metadata.copy()
                eggs_dict[sha256_key]['indexed_tag'] = python_tag
    return eggs_dict
