class_docstr: A file wrapper exposing the minimal interface to copy from.
class_docstr_tok: ["A","file","wrapper","exposing","the","minimal","interface","to","copy","from","."]
code: def readline(self):
      return self.f.readline()
  
imports: import io
  import sys
  import string
  import unittest
  from .testutils import ConnectingTestCase, skip_before_postgres, slow, StringIO
  from .testutils import skip_if_crdb
  from itertools import cycle
  from subprocess import Popen, PIPE
  import psycopg2
  import psycopg2.extensions
  from .testutils import skip_copy_if_green, TextIOBase
  from .testconfig import dsn
label_desc: Use image node_id 3 for calling the MinimalRead obj's underlying member method code with example usage: obj.readline() and returns: self