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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 robo_avatar_url(user_data, size=80):
 """Return the gravatar image for the given email address."""

    hash = md5(str(user_data).strip().lower().encode('utf-8')).hexdigest()
    url = "https://robohash.org/{hash}.png?size={size}x{size}".format(
        hash=hash, size=size)
    return url