def refresh(self):
        for i in range(self.num_buffers):
            if self.buffers[i] is None and i not in self.empty:
                self.buffers[i] = self.files[i].readline()

                if self.buffers[i] == "":
                    self.empty.add(i)
                    self.files[i].close()

        if len(self.empty) == self.num_buffers:
            return False

        return True