code: def decode_full_layer_uri(full_layer_uri_string):
      
      if not full_layer_uri_string:
          return None, None
  
      split = full_layer_uri_string.split('|qgis_provider=')
      if len(split) == 1:
          return split[0], None
      else:
          return split
docs: Decode the full layer URI.
  
      :param full_layer_uri_string: The full URI provided by our helper.
      :type full_layer_uri_string: basestring
  
      :return: A tuple with the QGIS URI and the provider key.
      :rtype: tuple