code: public void setRecipients(java.util.Collection<String> recipients) {
          if (recipients == null) {
              this.recipients = null;
              return;
          }
  
          this.recipients = new com.amazonaws.internal.SdkInternalList<String>(recipients);
      }
docs: <p>
  The recipient domains and email addresses that the receipt rule applies to. If this field is not specified, this
  rule will match all recipients under all verified domains.
  </p>
  
  @param recipients
  The recipient domains and email addresses that the receipt rule applies to. If this field is not
  specified, this rule will match all recipients under all verified domains.