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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 create(cls, name, sandbox_data_center, portal_username=None, comment=None):
 """ Create a Sandbox Service element """

        json = {
            'name': name,
            'sandbox_data_center': element_resolver(sandbox_data_center),
            'portal_username': portal_username if portal_username else '',
            'comment': comment}
        return ElementCreator(cls, json)