import random
import string
import io
from signedjson.key import generate_signing_key, write_signing_keys


def random_string(length):
    return ''.join(random.choice(string.ascii_letters) for _ in range(length))


key_id = "a_" + random_string(4)
with io.StringIO() as f:
    write_signing_keys(f, (generate_signing_key(key_id),),)
    f.seek(0)
    print(f.read())