code: def __len__(self):
      return int(np.ceil(self._num_windows / self._batch_size))
  
file_path: stellargraph/stellargraph/mapper/sliding.py
imports: import numpy
  from .None import Generator
  from tensorflow.keras.utils import Sequence
  from ..core.validation import require_integer_in_range
label_desc: Use image node_id 2 for calling the SlidingFeaturesNodeSequence obj's underlying member method code with example usage: obj.__len__() and returns: int