Method is

src/main/java/org/apache/commons/lang3/CharRange.java:87–89

Constructs a CharRange over a single character. @param ch only character in this range @return the new CharRange object @see CharRange#CharRange(char, char, boolean) @since 2.5

(final char ch)

     * @since 2.5
     */
    public static CharRange is(final char ch) {
        return new CharRange(ch, ch, false);
    }

    /**
     * <p>Constructs a negated {@code CharRange} over a single character.</p>