parameters: (cell_type, num_units)
return_statement: return cell_type(num_units=num_units)
docstring: Constructs and return a single `RNNCell`.
  
    Args:
      cell_type: Either a string identifying the `RNNCell` type or a subclass of
        `RNNCell`.
      num_units: The number of units in the `RNNCell`.
    Returns:
      An initialized `RNNCell`.
    Raises:
      ValueError: `cell_type` is an invalid `RNNCell` name.
      TypeError: `cell_type` is not a string or a subclass of `RNNCell`.
docstring_summary: Constructs and return a single `RNNCell`.
docstring_tokens: Constructs and return a single RNNCell .
function: def _get_single_cell(cell_type, num_units):
    """Constructs and return a single `RNNCell`.
  
    Args:
      cell_type: Either a string identifying the `RNNCell` type or a subclass of
        `RNNCell`.
      num_units: The number of units in the `RNNCell`.
    Returns:
      An initialized `RNNCell`.
    Raises:
      ValueError: `cell_type` is an invalid `RNNCell` name.
      TypeError: `cell_type` is not a string or a subclass of `RNNCell`.
    """
    cell_type = _CELL_TYPES.get(cell_type, cell_type)
    if not cell_type or not issubclass(cell_type, contrib_rnn.RNNCell):
      raise ValueError('The supported cell types are {}; got {}'.format(
          list(_CELL_TYPES.keys()), cell_type))
    return cell_type(num_units=num_units)
function_tokens: def _get_single_cell ( cell_type , num_units ) : cell_type = _CELL_TYPES . get ( cell_type , cell_type ) if not cell_type or not issubclass ( cell_type , contrib_rnn . RNNCell ) : raise ValueError ( 'The supported cell types are {}; got {}' . format ( list ( _CELL_TYPES . keys ( ) ) , cell_type ) ) return cell_type ( num_units = num_units )