def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def send(self, command):
        if self._bufferedCommands is None:
            self._bufferedCommands = command
        else:
            self._bufferedCommands += "\n" + command