code: public CreateGrantRequest withGrantTokens(String... grantTokens) {
          if (this.grantTokens == null) {
              setGrantTokens(new com.ibm.cloud.objectstorage.internal.SdkInternalList<String>(grantTokens.length));
          }
          for (String ele : grantTokens) {
              this.grantTokens.add(ele);
          }
          return this;
      }
docs: <p>
  A list of grant tokens.
  </p>
  <p>
  For more information, see <a
  href="http://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#grant_token">Grant Tokens</a> in the
  <i>AWS Key Management Service Developer Guide</i>.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setGrantTokens(java.util.Collection)} or {@link #withGrantTokens(java.util.Collection)} if you want to
  override the existing values.
  </p>
  
  @param grantTokens
  A list of grant tokens.</p>
  <p>
  For more information, see <a
  href="http://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#grant_token">Grant Tokens</a> in
  the <i>AWS Key Management Service Developer Guide</i>.
  @return Returns a reference to this object so that method calls can be chained together.