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   /*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.handler.codec.smtp;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  final class SmtpUtils {
  
      static List<CharSequence> toUnmodifiableList(CharSequence... sequences) {
          if (sequences == null || sequences.length == 0) {
              return Collections.emptyList();
          }
          return Collections.unmodifiableList(Arrays.asList(sequences));
      }
  
      private SmtpUtils() { }
  }