from typing import List


def create_id_access_token_header(id_access_token: str) -> List[str]:
    """Create an Authorization header for passing to SimpleHttpClient as the header value
    of an HTTP request.

    Args:
        id_access_token: An identity server access token.

    Returns:
        The ascii-encoded bearer token encased in a list.
    """
    # Prefix with Bearer
    bearer_token = "Bearer %s" % id_access_token

    # Encode headers to standard ascii
    bearer_token.encode("ascii")

    # Return as a list as that's how SimpleHttpClient takes header values
    return [bearer_token]