class_docstr: Arguments:
      predicate (AbstractExpression): A predicate expression used for
      filtering frames
code: def __str__(self):
      return "PredicatePlan(predicate={})".format(self.predicate)
  
imports: from evadb.expression.abstract_expression import AbstractExpression
  from evadb.plan_nodes.abstract_plan import AbstractPlan
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 2 for calling the PredicatePlan obj's underlying member method code with example usage: obj.__str__() and returns: str