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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 transform(self, word, column=Profile.GRAPHEME_COL, error=errors.replace):
 """ Transform a string's graphemes into the mappings given in a different column in the orthography profile. Parameters word : str The input string to be tokenized. column : str (default = "Grapheme") The label of the column to transform to. Default it to tokenize with orthography profile. Returns ------- result : list of lists Result of the transformation. """

        assert self.op, 'method can only be called with orthography profile.'

        if column != Profile.GRAPHEME_COL and column not in self.op.column_labels:
            raise ValueError("Column {0} not found in profile.".format(column))

        word = self.op.tree.parse(word, error)
        if column == Profile.GRAPHEME_COL:
            return word
        out = []
        for token in word:
            try:
                target = self.op.graphemes[token][column]
            except KeyError:
                target = self._errors['replace'](token)
            if target is not None:
                if isinstance(target, (tuple, list)):
                    out.extend(target)
                else:
                    out.append(target)
        return out