How to use the mediacloud.readability.readabilitytests.ReadabilityTool function in mediacloud

def demo(self):
        self = ReadabilityTool()
        text = """
                It is for us the living, rather,
                to be dedicated here to the unfinished
                work which they who fought here have
                thus far so nobly advanced. It is
                rather for us to be here dedicated
                to the great task remaining before us,
                that from these honored dead we take 
                increased devotion to that cause for which they
                gave the last full measure of devotion, that we
                here highly resolve that these dead shall not have
                died in vain, that this nation, under God, shall have a
                new birth of freedom, and that government of the people, by
                the people, for the people, shall not perish from this earth.  
               """

def demo():
    ReadabilityTool.demo()

def getFleshKincaidGradeLevel(text):
    '''
    Get the grade reading level of a piece of text.  This relies on patched ntlk_contrib
    code, stored in the mediacloud.readability module (cause the published code don't
    work!).
    '''
    r = ReadabilityTool()
    gradeLevel = None
    if isEnglish(text):
        try:
            if (text!=None) and (len(text)>0) :
                gradeLevel = r.FleschKincaidGradeLevel(text.encode('utf-8'))
        except (KeyError, UnicodeDecodeError):
            pass
    return gradeLevel