<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def isatty(file):
 """ Returns `True` if `file` is a tty. Most built-in Python file-like objects have an `isatty` member, but some user-defined types may not, so this assumes those are not ttys. """

    if (multiprocessing.current_process().name != 'MainProcess' or
        threading.current_thread().getName() != 'MainThread'):
        return False

    if hasattr(file, 'isatty'):
        return file.isatty()
    elif (OutStream is not None and
          isinstance(file, (OutStream, IPythonIOStream)) and
          ((hasattr(file, 'name') and file.name == 'stdout') or
           (hasattr(file, 'stream') and
               isinstance(file.stream, PyreadlineConsole)))):
        # File is an IPython OutStream or IOStream and
        #    File name is 'stdout' or
        #    File wraps a Console
        return True
    return False