code: def relation_convert_target2(self, rels):
      output_text = []
      for rel in rels:
          head = self.nan(rel["head"])
          relation = self.nan(rel["relation"])
          tail = self.nan(rel["tail"])
          if head == "" or relation == "" or tail == "":
              output_text.append(self.NAN)
              continue
          output_text.append(f"{relation}：{head},{tail}")
      output_text = "\n".join(output_text)
      if (
          len(
              output_text.replace(self.NAN, "")
              .replace("\n", "")
              .strip()
          )
          == 0
      ):
          return self.prefix + self.NAN
      return self.prefix + output_text
  
file_path: DeepKE/example/llm/InstructKGC/kg2instruction/convert/converter/re_converter.py
imports: import json
label_desc: Use image node_id 6 for calling the REConverter obj's underlying member method code with example usage: obj.relation_convert_target2(rels) and returns: unknown, unknown