'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.'

def __init__(self, avatar, reactor=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
