code: def _pre_action(self) -> None:
      super()._pre_action()
  
      self.remove_keys.add("stacked_style")
  
      self.data["stack"] = self.stacked_map.get(
          self.data.get("stacked_style") or "stack"
      )
  
      self.data["opacity"] = 0.7
  
imports: from typing import Any
  from superset.utils.core import as_list
  from .base import MigrateViz
label_desc: Use image node_id 1 for calling the MigrateAreaChart obj's underlying member method code with example usage: obj._pre_action() without return types