class_docstr: This plan is used for storing information required for union operations.
  
  Arguments:
      all: Bool
          UNION (deduplication) vs UNION ALL (non-deduplication)
code: def __init__(self, all: bool):
      self._all = all
      super().__init__(PlanOprType.UNION)
  
imports: from evadb.plan_nodes.abstract_plan import AbstractPlan
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 1 to create a new UnionPlan object from inherited base classes: AbstractPlan with example: obj = UnionPlan(all)