code: def _pad_1x1_to_3x3_tensor(self, kernel1x1):
      if kernel1x1 is None:
          return 0
      else:
          return nn.functional.pad(kernel1x1, [1, 1, 1, 1])
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.regularizer import L2Decay
  from paddle.nn.initializer import Constant
  from ppdet.modeling.ops import get_act_fn
  from ppdet.core.workspace import register, serializable
  from ..shape_spec import ShapeSpec
label_desc: Use image node_id 5 for calling the RepVggBlock obj's underlying member method code with example usage: obj._pad_1x1_to_3x3_tensor(kernel1x1) and returns: int, nn