class_docstr: Deal with case 3.
class_docstr_tok: ["Deal","with","case","3","."]
code: def collate_strategies(self) -> List[ShardingStrategy]:
      strategy_list = []
      index = self.op_data["index"].data
  
      for strategy_index, strategy in enumerate(
          self.predecessor_node.strategies_vector
      ):
          # the sharding spec for input in this case is a tuple of ShardingSpec.
          sharding_spec_for_input = strategy.output_sharding_specs[
              self.op_data["input"]
          ]
          dim_partition_dict_for_output = sharding_spec_for_input[
              index
          ].dim_partition_dict
          dim_partition_dict_mapping = {}
          communication_action_mapping = {}
          dim_partition_dict_mapping = {
              "output": dim_partition_dict_for_output,
          }
          sharding_spec_mapping = self.to_sharding_spec_mapping(
              dim_partition_dict_mapping
          )
          sharding_spec_mapping["input"] = sharding_spec_for_input
          input_sharding_info = f"get the {index} element from ("
          for sharding_spec in sharding_spec_for_input:
              input_sharding_info += (
                  f"{sharding_spec.sharding_sequence}, "
              )
          input_sharding_info += ")"
          name = f'{sharding_spec_mapping["output"].sharding_sequence} = {input_sharding_info}_{strategy_index}'
  
          strategy = self.get_sharding_strategy(
              name=name,
              sharding_spec_mapping=sharding_spec_mapping,
              communication_action_mapping=communication_action_mapping,
          )
  
          strategy_list.append(strategy)
  
      return strategy_list
  
file_path: colossalai/colossalai/auto_parallel/tensor_shard/node_handler/strategy/getitem_generator.py
imports: import copy
  from typing import List
  from colossalai.auto_parallel.tensor_shard.sharding_strategy import MemoryCost, ShardingStrategy, TrainCycleItem
  from colossalai.logging import get_dist_logger
  from colossalai.tensor.sharding_spec import ShardingSpecException
  from .strategy_generator import FollowingStrategyGenerator
label_desc: Use image node_id 1 for calling the TensorTupleStrategyGenerator obj's underlying member method code with example usage: obj.collate_strategies() and returns: strategy_list