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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 add_chain_ids(self, chains):
 """Add chains by ID into the chains attribute Args: chains (str, list):
 Chain ID or list of IDs """

        chains = ssbio.utils.force_list(chains)

        for c in chains:
            if self.chains.has_id(c):
                log.debug('{}: chain already present'.format(c))
            else:
                chain_prop = ChainProp(ident=c, pdb_parent=self.id)
                self.chains.append(chain_prop)
                log.debug('{}: added to chains list'.format(c))