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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 is_uswest_source(self):
 """Checks if data source via Sentinel Hub services is available at US West server Example: ``DataSource.LANDSAT8.is_uswest_source()`` or ``DataSource.is_uswest_source(DataSource.LANDSAT8)`` :param self: One of the supported data sources :type self: DataSource :return: ``True`` if data source exists at US West server and ``False`` otherwise :rtype: bool """

        return not SHConfig().is_eocloud_ogc_url() and self.value[0] in [_Source.LANDSAT8, _Source.MODIS, _Source.DEM]