code: def get_kinds(start=None, end=None):
    
    q = Kind.query()
    if start is not None and start != '':
      q = q.filter(Kind.key >= Kind.key_for_kind(start))
    if end is not None:
      if end == '':
        return []
      q = q.filter(Kind.key < Kind.key_for_kind(end))
  
    return [x.kind_name for x in q]
docs: Return all kinds in the specified range, for the current namespace.
  
    Args:
      start: only return kinds >= start if start is not None.
      end: only return kinds < end if end is not None.
  
    Returns:
      A list of kind names between the (optional) start and end values.