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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 _CollectHistoryAgg_(contactHist, fieldHistObj, fieldName):
 """ Return updated history dictionary with new field change :param dict contactHist: Existing contact history dictionary :param dict fieldHistObj: Output of _CollectHistory_ :param string fieldName: field name """


    if fieldHistObj!={}:
        if fieldName not in contactHist.keys():
            contactHist[fieldName] = {}
        for lookupType in fieldHistObj.keys():
            contactHist[fieldName][lookupType] = fieldHistObj[lookupType]

    return contactHist