class_docstr: Memory Efficient RowReader 
      
code: def __init__(self, nfeat, index):
      self.nfeat = nfeat
      self.loaded_nfeat = {}
      self.index = index
  
file_path: PGL/legacy/pgl/utils/op.py
imports: import numpy
  import paddle.fluid
  from pgl.utils import paddle_helper
label_desc: Use image node_id 1 to create a new RowReader object from inherited base classes: object with example: obj = RowReader(nfeat, index)