code: def pack_gzip(params, ctxt, scope, stream, coord):
      
      if len(params) == 0:
          raise errors.InvalidArguments(coord, "{} args".format(len(params)), "at least one argument")
      
      built = utils.binary("")
      for param in params:
          if isinstance(param, pfp.fields.Field):
              built += param._pfp__build()
          else:
              built += param
      
      return zlib.compress(built)
docs: ``PackGZip`` - Concats the build output of all params and gzips the
      resulting data, returning a char array.
  
      Example: ::
  
          char data[0x100]<pack=PackGZip, ...>;