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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 decipher(self,string):
 """Decipher string using Delastelle cipher according to initialised key. Example:: plaintext = Delastelle('APCZ WRLFBDKOTYUQGENHXMIVS').decipher(ciphertext) :param string: The string to decipher. :returns: The deciphered string. The plaintext will be 1/3 the length of the ciphertext. """
         
        string = self.remove_punctuation(string,filter='[^'+self.chars+']')
        ret = ''
        for i in range(0,len(string),3):
            ind = tuple([int(string[i+k]) for k in [0,1,2]])
            ret += IND2L[ind]
        return ret