* }</pre>
   *
   * ... returns {@code "aaa"}.
   */
  public String retainFrom(CharSequence sequence) {
    return negate().removeFrom(sequence);
  }

  /**
   * Returns a string copy of the input character sequence, with each matching BMP character
   * replaced by a given replacement character. For example:
   *
   * <pre>{@code
   * CharMatcher.is('a').replaceFrom("radar", 'o')
   * }</pre>
   *

   * }</pre>
   *
   * ... returns {@code "aaa"}.
   */
  public String retainFrom(CharSequence sequence) {
    return negate().removeFrom(sequence);
  }

  /**
   * Returns a string copy of the input character sequence, with each matching BMP character
   * replaced by a given replacement character. For example:
   *
   * <pre>{@code
   * CharMatcher.is('a').replaceFrom("radar", 'o')
   * }</pre>
   *