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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 _make_association(self, subject_id, object_id, rel_id, pubmed_ids):
 """ Make a reified association given an array of pubmed identifiers. Args: :param subject_id id of the subject of the association (gene/chem) :param object_id id of the object of the association (disease) :param rel_id relationship id :param pubmed_ids an array of pubmed identifiers Returns: :return None """


        # TODO pass in the relevant Assoc class rather than relying on G2P
        assoc = G2PAssoc(self.graph, self.name, subject_id, object_id, rel_id)
        if pubmed_ids is not None and len(pubmed_ids) > 0:
            for pmid in pubmed_ids:
                ref = Reference(
                    self.graph, pmid, self.globaltt['journal article'])
                ref.addRefToGraph()
                assoc.add_source(pmid)
                assoc.add_evidence(self.globaltt['traceable author statement'])

        assoc.add_association_to_graph()
        return