code: def sample(self):
      x = self.mean + self.std * paddle.randn(self.mean.shape)
      return x
  
imports: import numpy
  import paddle
  import paddle.nn
  from ..configuration_utils import ConfigMixin
  from ..configuration_utils import register_to_config
  from .unet_blocks import get_down_block
  from .unet_blocks import get_up_block
  from .unet_blocks import UNetMidBlock2D
label_desc: Use image node_id 2 for calling the DiagonalGaussianDistribution obj's underlying member method code with example usage: obj.sample() and returns: x