'function to check if a source is ready initializing'

def check_source(self, src):

    defer_param = defer.Deferred()
    def do_check():
        src_obj = self.boosting_manager.get_source_object(src)
        if (src_obj and src_obj.ready):
            self._check_source_lc.stop()
            self._check_source_lc = None
            defer_param.callback(src)
    self._check_source_lc = LoopingCall(do_check)
    self._check_source_lc.start(1, now=True)
    return defer_param
