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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 _process_cvterm(self):
 """ CVterms are the internal identifiers for any controlled vocab or ontology term. Many are xrefd to actual ontologies. The actual external id is stored in the dbxref table, which we place into the internal hashmap for lookup with the cvterm id. The name of the external term is stored in the "name" element of this table, and we add that to the label hashmap for lookup elsewhere :return: """


        line_counter = 0
        raw = '/'.join((self.rawdir, 'cvterm'))
        LOG.info("processing cvterms")

        with open(raw, 'r') as f:
            f.readline()  # read the header row; skip
            filereader = csv.reader(f, delimiter='\t', quotechar='\"')
            for line in filereader:
                line_counter += 1

                (cvterm_id, cv_id, definition, dbxref_id, is_obsolete,
                 is_relationshiptype, name) = line

                # 316 6 1665919 0 0 rRNA_cleavage_snoRNA_primary_transcript
                # 28  5 1663309 0 0 synonym
                # 455 6 1665920 0 0 tmRNA

                # not sure the following is necessary
                # cv_prefixes = {
                #     6 : 'SO',
                #     20: 'FBcv',
                #     28: 'GO',
                #     29: 'GO',
                #     30: 'GO',
                #     31: 'FBcv',  # not actually FBcv - I think FBbt.
                #     32: 'FBdv',
                #     37: 'GO',   # these are relationships
                #     73: 'DOID'
                # }

                # if int(cv_id) not in cv_prefixes:
                #     continue
                cvterm_key = cvterm_id
                cvterm_id = self._makeInternalIdentifier('cvterm', cvterm_key)
                self.label_hash[cvterm_id] = name
                self.idhash['cvterm'][cvterm_key] = cvterm_id
                # look up the dbxref_id for the cvterm
                # hopefully it's one-to-one
                dbxrefs = self.dbxrefs.get(dbxref_id)
                if dbxrefs is not None:
                    if len(dbxrefs) > 1:
                        LOG.info(
                            ">1 dbxref for this cvterm (%s: %s): %s",
                            str(cvterm_id), name, dbxrefs.values())
                    elif len(dbxrefs) == 1:
                        # replace the cvterm with
                        # the dbxref (external) identifier
                        did = dbxrefs.popitem()[1]
                        # get the value
                        self.idhash['cvterm'][cvterm_key] = did
                        # also add the label to the dbxref
                        self.label_hash[did] = name
        return