<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_resource_by_agent(self, agent_id):
 """Gets the ``Resource`` associated with the given agent. arg: agent_id (osid.id.Id):
 ``Id`` of the ``Agent`` return: (osid.resource.Resource) - associated resource raise: NotFound - ``agent_id`` is not found raise: NullArgument - ``agent_id`` is ``null`` raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure *compliance: mandatory -- This method must be implemented.* """

        collection = JSONClientValidated('resource',
                                         collection='Resource',
                                         runtime=self._runtime)
        result = collection.find_one(
            dict({'agentIds': {'$in': [str(agent_id)]}},
                 **self._view_filter()))
        return objects.Resource(
            osid_object_map=result,
            runtime=self._runtime,
            proxy=self._proxy)