docs: def import_registry(dest, src, api=None, profile=None, support=None,
                      filter_symbol=None):
      """Imports all features and extensions and all their dependencies.
  
      :param Registry dest: Destination API
      :param Registry src: Source Registry
      :param str api: Only import Features with API name `api`, or None
                      to import all features.
      :param str profile: Only import Features with profile name `profile`,
                          or None to import all features.
      :param str support: Only import Extensions with this extension support
                          string, or None to import all extensions.
      :param filter_symbol: Optional symbol filter callable
      :type filter_symbol: Callable with signature
                           ``(symbol_type:str, symbol_name:str) -> bool``
      """
      if filter_symbol is None:
          filter_symbol = _default_filter_symbol
      for x in src.get_features(api):
          import_feature(dest, src, x.name, api, profile, filter_symbol)
      for x in src.get_extensions(support):
          import_extension(dest, src, x.name, api, profile, filter_symbol)