public static final void assertInputStreamNotNull(InputStream is) throws IOException {
        if (is == null) {
            throw new IOException("input sream is null");
        }
    }
Checks if InputStream is not null

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