def __init__(self, avatar, reactor=None):
        """
        Construct an C{SSHSessionForUnixConchUser}.

        @param avatar: The L{UnixConchUser} for whom this is an SSH session.
        @param reactor: An L{IReactorProcess} used to handle shell and exec
            requests. Uses the default reactor if None.
        """
        if reactor is None:
            from twisted.internet import reactor
        self._reactor = reactor
        self.avatar = avatar
        self.environ = {'PATH': '/bin:/usr/bin:/usr/local/bin'}
        self.pty = None
        self.ptyTuple = 0

        Construct an C{SSHSessionForUnixConchUser}.

        @param avatar: The L{UnixConchUser} for whom this is an SSH session.
        @param reactor: An L{IReactorProcess} used to handle shell and exec
            requests. Uses the default reactor if None.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/unix.py