error:  unable to find type 'u6'
Below code raises unable to find type 'u6' error, is 'u6' not supported? then how can I achieve such format? thanks!

- id: address_codes
        type:
          switch-on: net_info.ip_type
          cases:
            0: u2
            1: u4
            **2: u6**
            3: u8