code: def get_charm_series(path):
      
      md = Path(path) / "metadata.yaml"
      if not md.exists():
          return None
      data = yaml.load(md.open())
      series = data.get('series')
      return series[0] if series else None
docs: Inspects the charm directory at ``path`` and returns a default
      series from its metadata.yaml (the first item in the 'series' list).
  
      Returns None if no series can be determined.