def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def __init__(self, host, loginUser, debug = False, trace = False, log=None, port=22, pexpectObject=None):
        self.pexpect = pexpect if not pexpectObject else pexpectObject
        self.debug = debug
        self.trace = trace
        self.host = host
        self._port = port
        self._connection = None
        self.modeList = []
        self._log = log
        self._bufferedCommands = None
        self._bufferedMode = None
        self._loginUser = loginUser
        self._resetExpect()