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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:
 def sign_hmac(secret, payload):
 """Returns a base64-encoded HMAC-SHA1 signature of a given string. :param secret: The key used for the signature, base64 encoded. :type secret: string :param payload: The payload to sign. :type payload: string :rtype: string """

    payload = payload.encode('ascii', 'strict')
    secret = secret.encode('ascii', 'strict')
    sig = hmac.new(base64.urlsafe_b64decode(secret), payload, hashlib.sha1)
    out = base64.urlsafe_b64encode(sig.digest())
    return out.decode('utf-8')