code: def parse(name, content, releases, get_head_fn):
      
      try:
          return {e["version"]: e["changelog"] for e in content["entries"]
                  if e["changelog"]}
      except KeyError:
          return {}
docs: Parses the given content for a valid changelog
      :param name: str, package name
      :param content: str, content
      :param releases: list, releases
      :param get_head_fn: function
      :return: dict, changelog