def __init__(self, optimizer, fraction=<NUM_LIT:0.1>, scope='<STR_LIT>', summary_labels=()):
assert isinstance(fraction, float) and fraction > <NUM_LIT:0.0><EOL>self.fraction = fraction<EOL>super(SubsamplingStep, self).__init__(optimizer=optimizer, scope=scope, summary_labels=summary_labels)<EOL>
Creates a new subsampling-step meta optimizer instance.

Args:
    optimizer: The optimizer which is modified by this meta optimizer.
    fraction: The fraction of instances of the batch to subsample.