docs: def read_dist_egginfo_json(dist, filename=DEFAULT_JSON):
      """
      Safely get a json within an egginfo from a distribution.
      """
  
      # use the given package's distribution to acquire the json file.
      if not dist.has_metadata(filename):
          logger.debug("no '%s' for '%s'", filename, dist)
          return
  
      try:
          result = dist.get_metadata(filename)
      except IOError:
          logger.error("I/O error on reading of '%s' for '%s'.", filename, dist)
          return
  
      try:
          obj = json.loads(result)
      except (TypeError, ValueError):
          logger.error(
              "the '%s' found in '%s' is not a valid json.", filename, dist)
          return
  
      logger.debug("found '%s' for '%s'.", filename, dist)
      return obj