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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 delete(self, key):
 """Delete method of CRUD operation for all data types. Args: key (string):
 The variable to write to the DB. Returns: (string):
 Result of DB write. """

        data = None
        if key is not None:
            data = self.db.delete(key.strip())
        else:
            self.tcex.log.warning(u'The key field was None.')
        return data