'Name scope to create the clone.
Args:
clone_index: Int, representing the clone_index.
Returns:
A name_scope suitable for `tf.name_scope()`.
Raises:
ValueError: if `clone_index` is greater or equal to the number of clones".'

def clone_scope(self, clone_index):

    if (clone_index >= self._num_clones):
        raise ValueError('clone_index    must    be    less    than    num_clones')
    scope = ''
    if (self._num_clones > 1):
        scope = ('clone_%d' % clone_index)
    return scope
