class_docstr: Visitor to perform graph annotation on an AST.
  
  Parameters
  ----------
  start: int
      the start location to mark run on vta (inclusive)
  end: int
      the end location to mark run on vta (exclusive)
  
  Returns
  ---------
  None
class_docstr_tok: ["Visitor","to","perform","graph","annotation","on","an","AST",".","Parameters","--","--","--","--","--","start",":","int","the","start","location","to","mark","run","on","vta","(","inclusive",")","end",":","int","the","end","location","to","mark","run","on","vta","(","exclusive",")","Returns","--","--","--","--","-","None"]
code: def __init__(self, start=-1, end=-1):
      self.ext_dev = tvm.device("ext_dev")
      self.cpu_dev = tvm.device("cpu")
      self.cast = op.op.get("cast")
      self.counter = -1
      self.start = start
      self.end = end
      super().__init__()
  
imports: import tvm
  from tvm import relay
  from tvm.relay import op, transform
  from tvm.relay import ExprMutator
label_desc: Use image node_id 1 to create a new ExprDeviceAnnot object from inherited base classes: ExprMutator with example: obj = ExprDeviceAnnot(start, end)