<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_subnet_id(self, name):
 """ Return subnet ID for given ``name``, if it exists. E.g. with a subnet mapping of ``{'abc123': 'ops', '67fd56': 'prod'}``, ``get_subnet_id('ops')`` would return ``'abc123'``. If the map has non-unique values, the first matching key will be returned. If no match is found, the given ``name`` is returned as-is. This works well for e.g. normalizing names-or-IDs to just IDs. """

        for subnet_id, subnet_name in self.config['subnets'].iteritems():
            if subnet_name == name:
                return subnet_id
        return name