public static final void assertChmAccessorNotNull(ChmAccessor<?> chmAccessor)
            throws ChmParsingException {
        if (chmAccessor == null) {
            throw new ChmParsingException("chm header is null");
        }
    }
Checks if ChmAccessor is not null In case of null throws exception

@param chmAccessor
@throws ChmParsingException
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/chm/ChmAssert.java