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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 getextensibleindex(bunchdt, data, commdct, key, objname):
 """get the index of the first extensible item"""

    theobject = getobject(bunchdt, key, objname)
    if theobject == None:
        return None
    theidd = iddofobject(data, commdct, key)
    extensible_i = [
        i for i in range(len(theidd)) if 'begin-extensible' in theidd[i]]
    try:
        extensible_i = extensible_i[0]
    except IndexError:
        return theobject