class_docstr: A base class providing the backwards-compatible spawn API for Pexpect.
  
  This should not be instantiated directly: use :class:`pexpect.spawn` or
  :class:`pexpect.fdpexpect.fdspawn`.
docstr: Overridden in subclass using tty
docstr_tok: ["Overridden","in","subclass","using","tty"]
code: def isatty(self):
      """Overridden in subclass using tty"""
      return False
  
imports: from io import StringIO, BytesIO
  import codecs
  import os
  import sys
  import re
  import errno
  from .exceptions import ExceptionPexpect, EOF, TIMEOUT
  from .expect import Expecter, searcher_string, searcher_re
label_desc: Use image node_id 21 for calling the SpawnBase obj's underlying member method code with example usage: obj.isatty() and returns: False