class_docstr: This plan is used for storing information required for group by
  operations.
  
  Arguments:
      groupby_clause: ConstantValueExpression
          A ConstantValueExpression which is the number of elements to
          group together.
code: def __hash__(self) -> int:
      return hash((super().__hash__(), self.groupby_clause))
  
file_path: evadb/evadb/plan_nodes/groupby_plan.py
imports: from evadb.expression.constant_value_expression import ConstantValueExpression
  from evadb.plan_nodes.abstract_plan import AbstractPlan
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 4 for calling the GroupByPlan obj's underlying member method code with example usage: obj.__hash__() and returns: hash