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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 createMedian(imgObjList, configObj, procSteps=None):
 """ Top-level interface to createMedian step called from top-level AstroDrizzle. This function parses the input parameters then calls the `_median()` function to median-combine the input images into a single image. """

    if imgObjList is None:
        msg = "Please provide a list of imageObjects to the median step"
        print(msg, file=sys.stderr)
        raise ValueError(msg)

    if procSteps is not None:
        procSteps.addStep('Create Median')

    step_name = util.getSectionName(configObj, _step_num_)
    if not configObj[step_name]['median']:
        log.info('Median combination step not performed.')
        return

    paramDict = configObj[step_name]
    paramDict['proc_unit'] = configObj['proc_unit']

    # include whether or not compression was performed
    driz_sep_name = util.getSectionName(configObj, _single_step_num_)
    driz_sep_paramDict = configObj[driz_sep_name]
    paramDict['compress'] = driz_sep_paramDict['driz_sep_compress']

    log.info('USER INPUT PARAMETERS for Create Median Step:')
    util.printParams(paramDict, log=log)

    _median(imgObjList, paramDict)

    if procSteps is not None:
        procSteps.endStep('Create Median')