code: def vars(self) -> List[Variable]:
      return sorted(
          set.union(
              *[
                  x.arg.st.vars()
                  for x in self.lazyops
                  if x.op in BufferOps
              ],
              set(),
          ),
          key=lambda x: str(x.expr),
      )
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, Union, Type, Tuple, Any, List, Dict, Callable, ClassVar
  import functools
  from enum import Enum, auto
  from tinygrad.helpers import prod, dedup
  from tinygrad.dtype import dtypes, DType
  from tinygrad.shape.symbolic import Variable
  from dataclasses import dataclass
label_desc: Use image node_id 7 for calling the LazyOp obj's underlying member method code with example usage: obj.vars() and returns: sorted