:return: docker tag to be used for the container

def get_docker_tag(platform: str, registry: str) -> str:
    """:return: docker tag to be used for the container"""
    platform = platform if any(x in platform for x in ['build.', 'publish.']) else 'build.{}'.format(platform)
    if not registry:
        registry = "mxnet_local"
    return "{0}/{1}".format(registry, platform)