class_docstr: Read X,y from an SVMlight file, and produce [X_i, y_i] pairs. 
class_docstr_tok: ["Read","X",",","y","from","an","SVMlight","file",",","and","produce","[","X_i",",","y_i","]","pairs","."]
code: def __len__(self):
      return len(self.y)
  
imports: import numpy
  import os
  import six
  from ..utils import logger
  from ..utils.argtools import log_once
  from ..utils.serialize import loads
  from ..utils.develop import create_dummy_class
  from ..utils.loadcaffe import get_caffe_pb
  from ..utils.timer import timed_operation
  from ..utils.utils import get_tqdm
  from .base import DataFlowReentrantGuard, RNGDataFlow
  from .common import MapData
label_desc: Use image node_id 2 for calling the SVMLightData obj's underlying member method code with example usage: obj.__len__() and returns: len