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 __init__(self, groupby_clause: ConstantValueExpression):
      self._groupby_clause = groupby_clause
      super().__init__(PlanOprType.GROUP_BY)
  
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 1 to create a new GroupByPlan object from inherited base classes: AbstractPlan with example: obj = GroupByPlan(groupby_clause)