code: def _ord_to_namespace(n, _max_length=None):
    
    if _max_length is None:
      _max_length = MAX_NAMESPACE_LENGTH
  
    length = _LEX_DISTANCE[_max_length - 1]
    if n == 0:
      return ''
    n -= 1
    return (NAMESPACE_CHARACTERS[n / length] +
            _ord_to_namespace(n % length, _max_length - 1))
docs: Convert a namespace ordinal to a namespace string.
  
    Converts an int, representing the sequence number of a namespace ordered
    lexographically, into a namespace string.
  
    >>> _ord_to_namespace(0)
    ''
    >>> _ord_to_namespace(1)
    '-'
    >>> _ord_to_namespace(2)
    '--'
    >>> _ord_to_namespace(3)
    '---'
  
    Args:
      n: A number representing the lexographical ordering of a namespace.
      _max_length: The maximum namespace length.
    Returns:
      A string representing the nth namespace in lexographical order.