Process the mappings for a Frame Relay switch. Removes duplicates and
        adds the mappings to the node properties

def process_mappings(self):
        """
        Process the mappings for a Frame Relay switch. Removes duplicates and
        adds the mappings to the node properties
        """
        for mapping_a in self.mappings:
            for mapping_b in self.mappings:
                if mapping_a['source'] == mapping_b['dest']:
                    self.mappings.remove(mapping_b)
                    break

        self.node['properties']['mappings'] = {}
        mappings = self.node['properties']['mappings']
        for mapping in self.mappings:
            mappings[mapping['source']] = mapping['dest']