<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def AnalyzeDex(filename, session=None):
 """ Analyze an android dex file and setup all stuff for a more quickly analysis ! :param filename: the filename of the android dex file or a buffer which represents the dex file :type filename: string :param session: A session (Default None) :rtype: return a tuple of (sha256hash, :class:`DalvikVMFormat`, :class:`Analysis`) """

    log.debug("AnalyzeDex")

    if not session:
        session = get_default_session()

    with open(filename, "rb") as fd:
        data = fd.read()

    return session.addDEX(filename, data)