code: public void setEntityTypes(java.util.Collection<String> entityTypes) {
          if (entityTypes == null) {
              this.entityTypes = null;
              return;
          }
  
          this.entityTypes = new java.util.ArrayList<String>(entityTypes);
      }
docs: <p>
  The type of entity. The following can be returned:
  </p>
  <ul>
  <li>
  <p>
  <i>KEY</i> - An identifier for a field on the document.
  </p>
  </li>
  <li>
  <p>
  <i>VALUE</i> - The field text.
  </p>
  </li>
  </ul>
  <p>
  <code>EntityTypes</code> isn't returned by <code>DetectDocumentText</code> and
  <code>GetDocumentTextDetection</code>.
  </p>
  
  @param entityTypes
  The type of entity. The following can be returned:</p>
  <ul>
  <li>
  <p>
  <i>KEY</i> - An identifier for a field on the document.
  </p>
  </li>
  <li>
  <p>
  <i>VALUE</i> - The field text.
  </p>
  </li>
  </ul>
  <p>
  <code>EntityTypes</code> isn't returned by <code>DetectDocumentText</code> and
  <code>GetDocumentTextDetection</code>.
  @see EntityType