class_docstr: The variable table frame.
  A frame of variable table stores the variables created in one block or scope.
  
  Parameters
  ----------
  vars : Set[str]
      The set of variable names in the variable table frame.
class_docstr_tok: ["The","variable","table","frame",".","A","frame","of","variable","table","stores","the","variables","created","in","one","block","or","scope",".","Parameters","--","--","--","--","--","vars",":","Set","[","str","]","The","set","of","variable","names","in","the","variable","table","frame","."]
docstr: Add a new variable into variable table frame.
  
  Parameters
  ----------
  var : str
      The name of new variable.
code: def add(self, var: str):
      """Add a new variable into variable table frame.
  
      Parameters
      ----------
      var : str
          The name of new variable.
      """
      if var in self.vars:
          raise ValueError(
              f"Variable {var} already defined in current scope"
          )
      self.vars.add(var)
  
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 2 for calling the VarTableFrame obj's underlying member method code with example usage: obj.add(var) without return types