docs: def register(cls, name, encode, decode):
          """Add a codec to the registry.
  
          Registers a codec with the given `name` (a string) to be used with the
          given `encode` and `decode` functions, which take a `bytes` object and
          return another one.  An existing codec is replaced.
  
          >>> import binascii
          >>> CodecReg.register('uu', binascii.b2a_uu, binascii.a2b_uu)
          >>> CodecReg.get_decoder('uu') is binascii.a2b_uu
          True
          >>> CodecReg.reset()
          >>> 'uu' in CodecReg
          False
          """
          cls._codecs[name] = cls._codec(encode, decode)