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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 build_referenceWCS(catalog_list):
 """ Compute default reference WCS from list of Catalog objects. """

    wcslist = []
    for catalog in catalog_list:
        for scichip in catalog.catalogs:
            wcslist.append(catalog.catalogs[scichip]['wcs'])
    return utils.output_wcs(wcslist)