docs: def _has_bad_coords(root, stream):
      """
      Predicate function encapsulating 'data clean up' filter code.
  
      Currently minimal, but these sort of functions tend to grow over time.
  
      Problem 1:
          Some of the GCN packets have an RA /Dec equal to (0,0) in the WhereWhen,
          and a flag in the What signifying that those are actually dummy co-ords.
          (This is used for time-stamping an event which is not localised).
          So, we don't load those positions, to avoid muddying the database
          corpus.
      Problem 2:
          com.dc3/dc3.broker#BrokerTest packets have dummy RA/Dec values,
          with no units specified.
          (They're also marked role=test, so it's not such a big deal,
          but it generates a lot of debug-log churn.)
      """
      if stream == "com.dc3/dc3.broker":
          return True
      if not stream.split('/')[0] == 'nasa.gsfc.gcn':
          return False
      toplevel_params = vp.get_toplevel_params(root)
      if "Coords_String" in toplevel_params:
          if (toplevel_params["Coords_String"]['value'] ==
                  "unavailable/inappropriate"):
              return True
  
      return False