code: def get_backreferences(context, relationship=None, as_brains=None):
      
  
      instance = context.aq_base
      raw_backrefs = get_storage(instance)
  
      if not relationship:
          assert not as_brains, "You cannot use as_brains with no relationship"
          return raw_backrefs
  
      backrefs = list(raw_backrefs.get(relationship, []))
      if not backrefs:
          return []
  
      if not as_brains:
          return backrefs
  
      cat = _get_catalog_for_uid(backrefs[0])
      return cat(UID=backrefs)
docs: Return all objects which use a UIDReferenceField to reference context.
  
      :param context: The object which is the target of references.
      :param relationship: The relationship name of the UIDReferenceField.
      :param as_brains: Requests that this function returns only catalog brains.
          as_brains can only be used if a relationship has been specified.
  
      This function can be called with or without specifying a relationship.
  
      - If a relationship is provided, the return value will be a list of items
        which reference the context using the provided relationship.
  
        If relationship is provided, then you can request that the backrefs
        should be returned as catalog brains.  If you do not specify as_brains,
        the raw list of UIDs will be returned.
  
      - If the relationship is not provided, then the entire set of
        backreferences to the context object is returned (by reference) as a
        dictionary.  This value can then be modified in-place, to edit the stored
        backreferences.