public static String deleteAny(String inString, String charsToDelete) {
        if (!hasLength(inString) || !hasLength(charsToDelete)) {
            return inString;
        }
        
        int lastCharIndex = 0;
        char[] result = new char[inString.length()];
        for (int i = 0; i < inString.length(); i++) {
            char c = inString.charAt(i);
            if (charsToDelete.indexOf(c) == -1) {
                result[lastCharIndex++] = c;
            }
        }
        if (lastCharIndex == inString.length()) {
            return inString;
        }
        return new String(result, 0, lastCharIndex);
    }
@Test
    void testDeleteAny() {
        // Test case 1: inString is empty, charsToDelete is empty
        String inString1 = "";
        String charsToDelete1 = "";
        assertEquals("", StringUtils.deleteAny(inString1, charsToDelete1));
        
        // Test case 2: inString is empty, charsToDelete is not empty
        String inString2 = "";
        String charsToDelete2 = "abc";
        assertEquals("", StringUtils.deleteAny(inString2, charsToDelete2));
        
        // Test case 3: inString is not empty, charsToDelete is empty
        String inString3 = "abc";
        String charsToDelete3 = "";
        assertEquals("abc", StringUtils.deleteAny(inString3, charsToDelete3));
        
        // Test case 4: inString is not empty, charsToDelete is not empty
        String inString4 = "abc";
        String charsToDelete4 = "a";
        assertEquals("bc", StringUtils.deleteAny(inString4, charsToDelete4));
        
        // Test case 5: inString contains special characters
        String inString5 = "abc\n";
        String charsToDelete5 = "\n";
        assertEquals("abc", StringUtils.deleteAny(inString5, charsToDelete5));
        
        // Test case 6: inString not contains special characters
        String inString6 = "abc\n";
        String charsToDelete6 = "d";
        assertEquals("abc\n", StringUtils.deleteAny(inString6, charsToDelete6));
    }