class_docstr: Evaluator for property optimization task. Metric is top-3 property scores among generated molecules.
  
  Args:
      prop_name (str): A string indicating the name of the molecular property, use 'plogp' for penalized logP or 'qed' for 
          Quantitative Estimate of Druglikeness (QED). (default: :obj:`plogp`)
code: def __init__(self, prop_name="plogp"):
      assert prop_name in ["plogp", "qed"]
      self.prop_name = prop_name
  
file_path: DIG/dig/ggraph/evaluation/metric.py
imports: from rdkit import Chem
  import numpy
  from dig.ggraph.utils import check_chemical_validity, qed, calculate_min_plogp, reward_target_molecule_similarity
label_desc: Use image node_id 1 to create a new PropOptEvaluator object  with example: obj = PropOptEvaluator(prop_name)