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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 delete_interface_from_router(self, segment_id, router_name, server):
 """Deletes an interface from existing HW router on Arista HW device. :param segment_id: VLAN Id associated with interface that is added :param router_name: globally unique identifier for router/VRF :param server: Server endpoint on the Arista switch to be configured """


        if not segment_id:
            segment_id = DEFAULT_VLAN
        cmds = []
        for c in self._interfaceDict['remove']:
            cmds.append(c.format(segment_id))

        self._run_config_cmds(cmds, server)