code: def transformer_symshard_h4():
      """4 heads per shard."""
      hparams = transformer_symshard_base()
      hparams.encoder_layers = (
          "n,multihead-att,m,d,a," "n,ffn,m,d,a,"
      ) * 6 + "n,d"
      hparams.decoder_layers = (
          "n,multihead-att,m,d,a,"
          "n,enc-multihead-att,m,d,a,"
          "n,ffn,m,d,a,"
      ) * 6 + "n,d"
      return hparams
  
file_path: tensor2tensor/tensor2tensor/models/research/transformer_symshard.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from six.moves import range
  from tensor2tensor.layers import common_attention
  from tensor2tensor.layers import common_hparams
  from tensor2tensor.layers import common_layers
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import expert_utils
  from tensor2tensor.utils import registry
  from tensor2tensor.utils import t2t_model
  import tensorflow.compat.v1
label_desc: Use image node_id 5 for calling a global function with example usage: transformer_symshard_h4() and returns: hparams