class_docstr: Memory Efficient RowReader 
      
class_docstr_tok: ["Memory","Efficient","RowReader"]
code: def __init__(self, nfeat, index):
      self.nfeat = nfeat
      self.loaded_nfeat = {}
      self.index = index
  
file_path: PGL/pgl/utils/op.py
imports: import paddle
  from paddle import _C_ops, _legacy_C_ops
  import numpy
  from pgl.utils.helper import check_is_tensor
label_desc: Use image node_id 1 to create a new RowReader object from inherited base classes: dict with example: obj = RowReader(nfeat, index)