code: def get_valid_statements_for_modeling(sts: List[Influence]) -> List[Influence]:
      
  
      return [
          s
          for s in sts
          if is_grounded_statement(s)
          and (s.subj_delta["polarity"] is not None)
          and (s.obj_delta["polarity"] is not None)
      ]
docs: Select INDRA statements that can be used to construct a Delphi model
      from a given list of statements.