class_docstr: Wraps gfile.ReadableFile to add iteration, enter/exit and readlines.
code: def readlines(self):
      lines = []
      while True:
          ok, line = self._file.Readline()
          if ok:
              lines.append(line)
          else:
              break
      return lines
  
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 6 for calling the ReadableFile obj's underlying member method code with example usage: obj.readlines() and returns: lines