Return the type of the file

        @param filename : the filename
        @rtype : "APK", "DEX", None

def is_android(filename):
    """Return the type of the file

        @param filename : the filename
        @rtype : "APK", "DEX", None
    """
    if not filename:
        return None

    with open(filename, "rb") as fd:
        f_bytes = fd.read()
        return is_android_raw(f_bytes)

    return None