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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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