docstr: check if region start and end is legal
docstr_tok: ["check","if","region","start","and","end","is","legal"]
code: def check_region_start_end(
      self,
      start_node: Node,
      start_dim: int,
      start_idx: int,
      end_node: Node,
      end_dim: int,
      end_idx: int,
  ) -> bool:
      """
      check if region start and end is legal
      """
      # dim cannot be None
      if (
          get_node_shape(end_node) is None
          or get_node_shape(start_node) is None
      ):
          return False
      # dim size cannot be 1
      if (
          get_node_shape(end_node)[end_dim] == 1
          or get_node_shape(start_node)[start_dim] == 1
      ):
          return False
      # must have users
      if len(end_node.users) == 0:
          return False
      # check index source align
      if not self.check_index_source(
          start_dim, start_node, start_idx, end_dim, end_node
      ):
          return False
      # check index compute
      if not self.check_index_compute(
          start_idx, end_dim, end_node, end_idx
      ):
          return False
      return True
  
file_path: colossalai/colossalai/autochunk/trace_flow.py
imports: from typing import Dict, List, Tuple
  from torch.fx.node import Node
  from .trace_indice import TraceIndice
  from .utils import NodeMgr, find_chunk_all_input_nodes, find_chunk_compute_input_and_output_nodes, find_tensor_shape_node, flat_list, get_node_name, get_node_shape, is_non_compute_node
label_desc: Use image node_id 13 for calling the TraceFlow obj's underlying member method code with example usage: obj.check_region_start_end(start_node, start_dim, start_idx, end_node, end_dim, end_idx) and returns: True, False, False, False, False, False