code: def _update_table_fallbacks(self, table_toplevels):
          
  
          if len(self.elements) <= 1:
              return
  
          def parent_of(toplevel):
              # Returns an TopLevel parent of the given entry, or None.
              for parent_toplevel in table_toplevels:
                  if toplevel.name.sub_names[:-1] == parent_toplevel.name.sub_names:
                      return parent_toplevel
  
          for entry in table_toplevels:
              if entry.name.is_qualified:
                  parent = parent_of(entry)
                  if parent:
                      child_name = entry.name.without_prefix(parent.name)
                      parent.table_element.set_fallback({child_name.sub_names[0]: entry.table_element})
docs: Updates the fallbacks on all the table elements to make relative table access possible.
  
          Raises DuplicateKeysError if appropriate.