class_docstr: The TVMScript parser
  
  Parameters
  ----------
  diag : Diagnostics
      The diagnostics for error reporting.
  
  dispatch_tokens : List[str]
      The list of dispatching tokens to dispatching parsing method
      of different IRs and different doc AST structure.
  
  var_table : VarTable
      The variable table for parsing.
class_docstr_tok: ["The","TVMScript","parser","Parameters","--","--","--","--","--","diag",":","Diagnostics","The","diagnostics","for","error","reporting",".","dispatch_tokens",":","List","[","str","]","The","list","of","dispatching","tokens","to","dispatching","parsing","method","of","different","IRs","and","different","doc","AST","structure",".","var_table",":","VarTable","The","variable","table","for","parsing","."]
docstr: Check whether duplicate lhs exists in assignment.
  
  Parameters
  ----------
  target : doc.expr
      The doc AST expr node for lhs.
  
  Returns
  -------
  res : Union[bool, Set[str]]
      The result of true if duplicate lhs exists,
      or the set of lhs names if no duplicate lhs exists.
code: def _duplicate_lhs_check(
      self, target: doc.expr
  ) -> Union[bool, Set[str]]:
      """Check whether duplicate lhs exists in assignment.
  
      Parameters
      ----------
      target : doc.expr
          The doc AST expr node for lhs.
  
      Returns
      -------
      res : Union[bool, Set[str]]
          The result of true if duplicate lhs exists,
          or the set of lhs names if no duplicate lhs exists.
      """
      if isinstance(target, (doc.Tuple, doc.List)):
          vars: Set[str] = set()  # pylint: disable=redefined-builtin
          for i in target.elts:
              res = self._duplicate_lhs_check(i)
              if isinstance(res, bool) and res:
                  return True
              assert isinstance(res, set)
              if vars & res:
                  return True
              vars = vars.union(res)
          return vars
      elif isinstance(target, doc.Name):
          return {target.id}
      elif isinstance(target, doc.Starred):
          return self._duplicate_lhs_check(target.value)
      else:
          self.report_error(target, "Invalid type in assign statement")
          raise NotImplementedError
  
imports: import abc
  import inspect
  from collections import defaultdict
  from contextlib import contextmanager
  from typing import Any, Callable, Dict, List, Optional, Set, Union
  import numpy
  from tvm._ffi.base import TVMError
  from tvm.error import DiagnosticError
  from tvm.ir import GlobalVar
  from .None import dispatch, doc
  from .diagnostics import Diagnostics, Source
  from .evaluator import eval_assign, eval_expr
label_desc: Use image node_id 6 for calling the Parser obj's underlying member method code with example usage: obj._duplicate_lhs_check(target) and returns: vars, unknown, True, True, self