def encipher(self,string):
string = self.remove_punctuation(string)  <EOL>ret = '<STR_LIT>'<EOL>for (i,c) in enumerate(string):<EOL><INDENT>i = i%len(self.key)<EOL>ret += self.i2a(self.a2i(c) + self.key[i])<EOL><DEDENT>return ret<EOL>
Encipher string using Gronsfeld cipher according to initialised key. Punctuation and whitespace
        are removed from the input.       

        Example::

            ciphertext = Gronsfeld([5, 4, 7, 9, 8, 5, 8, 2, 0, 9, 8, 4, 3]).encipher(plaintext)     

        :param string: The string to encipher.
        :returns: The enciphered string.