def gravatar(email):
    hashed_email = md5.new(email).hexdigest()
    return mark_safe(GRAVATAR_URL % {
        'hash': hashed_email,
        'rating': GRAVATAR_MAX_RATING, 
        'size': GRAVATAR_SIZE,
        'default': urllib.quote_plus(GRAVATAR_DEFAULT_IMG),
    })
Takes an e-mail address and returns a gravatar image URL, using properties
dataset/ETHPy150Open caseywstark/colab/colab/apps/threadedcomments/templatetags/gravatar.py/gravatar