class_docstr: This module is used in RetinaNet to generate extra layers, P6 and P7.
  Serves as an ``extra_blocks``
  in :class:`~monai.networks.blocks.feature_pyramid_network.FeaturePyramidNetwork` .
code: def forward(
      self, results: list[Tensor], x: list[Tensor], names: list[str]
  ) -> tuple[list[Tensor], list[str]]:
      p5, c5 = results[-1], x[-1]
      x5 = p5 if self.use_P5 else c5
      p6 = self.p6(x5)
      p7 = self.p7(F.relu(p6))
      results.extend([p6, p7])
      names.extend(["p6", "p7"])
      return results, names
  
imports: from __future__ import annotations
  from collections import OrderedDict
  from collections.abc import Callable
  import torch.nn.functional
  from torch import Tensor, nn
  from monai.networks.layers.factories import Conv, Pool
label_desc: Use image node_id 2 for calling the LastLevelP6P7 obj's underlying member method code with example usage: obj.forward(results, x, names) and returns: results,  names