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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 _prepare_headers(self, request, filter=None, order_by=None, group_by=[], page=None, page_size=None):
 """ Prepare headers for the given request Args: request: the NURESTRequest to send filter: string order_by: string group_by: list of names page: int page_size: int """


        if filter:
            request.set_header('X-Nuage-Filter', filter)

        if order_by:
            request.set_header('X-Nuage-OrderBy', order_by)

        if page is not None:
            request.set_header('X-Nuage-Page', str(page))

        if page_size:
            request.set_header('X-Nuage-PageSize', str(page_size))

        if len(group_by) > 0:
            header = ", ".join(group_by)
            request.set_header('X-Nuage-GroupBy', 'true')
            request.set_header('X-Nuage-Attributes', header)