'Calculates the sha1 hash of a given string
:example \'b5d86317c2a144cd04d0d7c03b2b02666fafadf2\''

@classmethod
def sha1(cls, raw_output=False):

    res = hashlib.sha1(str(random.random()).encode(u'utf-8'))
    if raw_output:
        return res.digest()
    return res.hexdigest()
