class_docstr: Wraps gfile.ReadableFile to add iteration, enter/exit and readlines.
code: def __init__(self, filename):
      self._file = gfile.ReadableFile.New(filename)
  
file_path: deepvariant/third_party/nucleus/io/gfile.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import six
  from third_party.nucleus.io.python import gfile
label_desc: Use image node_id 1 to create a new ReadableFile object from inherited base classes: six with example: obj = ReadableFile(filename)