code: @Override
      public List<ProposalPersonContract> getKeyPersons(ProposalDevelopmentDocumentContract pdDoc) {
          List<ProposalPersonContract> keyPersons = new ArrayList<>();
          if (pdDoc != null) {
              for (ProposalPersonContract person : pdDoc.getDevelopmentProposal().getProposalPersons()) {
                  if (person.isKeyPerson()) {
                      keyPersons.add(person);
                  }
              }
          }
          return keyPersons;
      }
docs: Finds all the key Person associated with the provided pdDoc.