class_docstr: Wraps gfile.ReadableFile to add iteration, enter/exit and readlines.
code: def __exit__(self, type_, value, traceback):
      self._file.__exit__()
  
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 3 for calling the ReadableFile obj's underlying member method code with example usage: obj.__exit__(type_, value, traceback) without return types