code: def _expand_interface_name(self, interface_brief):
          
          if self.interface_map.get(interface_brief):
              return self.interface_map.get(interface_brief)
          command = 'show int {}'.format(interface_brief)
          output = self._send_command(command)
          first_line = output.splitlines()[0]
          if 'line protocol' in first_line:
              full_int_name = first_line.split()[0]
              self.interface_map[interface_brief] = full_int_name
              return self.interface_map.get(interface_brief)
          else:
              return interface_brief
docs: Obtain the full interface name from the abbreviated name.
  
          Cache mappings in self.interface_map.