code: def render_contributors(prs: List, fmt: str = "rst"):  # noqa
      "Find unique authors and print a list in  given format"
      authors = sorted(
          {pr["user"]["login"] for pr in prs}, key=lambda x: x.lower()
      )
  
      header = "Contributors"
      if fmt == "github":
          print(f"### {header}")  # noqa
          print(", ".join(f"@{user}" for user in authors))  # noqa
      elif fmt == "rst":
          print(header)  # noqa
          print("~" * len(header), end="\n\n")  # noqa
          print(",\n".join(f":user:`{user}`" for user in authors))
  
file_path: sktime/build_tools/changelog.py
imports: import os
  from collections import defaultdict
  from typing import Dict, List
  import httpx
  from dateutil import parser
label_desc: Use image node_id 5 for calling a global function with example usage: render_contributors(prs, fmt) without return types