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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 get_base_url(self, request):
 """ Creates base url string. :param request: OGC-type request with specified bounding box, cloud coverage for specific product. :type request: OgcRequest or GeopediaRequest :return: base string for url to Sentinel Hub's OGC service for this product. :rtype: str """

        url = self.base_url + request.service_type.value
        # These 2 lines are temporal and will be removed after the use of uswest url wont be required anymore:
        if hasattr(request, 'data_source') and request.data_source.is_uswest_source():
            url = 'https://services-uswest2.sentinel-hub.com/ogc/{}'.format(request.service_type.value)

        if hasattr(request, 'data_source') and request.data_source not in DataSource.get_available_sources():
            raise ValueError("{} is not available for service at ogc_base_url={}".format(request.data_source,
                                                                                         SHConfig().ogc_base_url))
        return url