code: def get_coherent_next_tag(prev_label: str, cur_label: str) -> str:
      
      if cur_label == "O":
          # Don't need to add prefix to an "O" label
          return "O"
  
      if prev_label == cur_label:
          return f"I-{cur_label}"
      else:
          return f"B-{cur_label}"
docs: Generate a coherent tag, given previous tag and current label.