def __init__(self,
               namespace_start=None,
               namespace_end=None,
               _app=None):
    """Initializes a NamespaceRange instance.

    Args:
      namespace_start: A string representing the start of the namespace range.
          namespace_start is included in the range. If namespace_start is None
          then the lexographically first namespace is used.
      namespace_end: A string representing the end of the namespace range.
          namespace_end is included in the range and must be >= namespace_start.
          If namespace_end is None then the lexographically last namespace is
          used.

    Raises:
      ValueError: if namespace_start > namespace_end.
    """
    if namespace_start is None:
      namespace_start = MIN_NAMESPACE

    if namespace_end is None:
      namespace_end = MAX_NAMESPACE

    if namespace_start > namespace_end:
      raise ValueError('namespace_start (%r) > namespace_end (%r)' % (
          namespace_start, namespace_end))
    self.__namespace_start = namespace_start
    self.__namespace_end = namespace_end
    self.__app = _app
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/namespace_range.py/NamespaceRange.__init__/original