code: def instruction_size(op, opc):
      
      if op < opc.HAVE_ARGUMENT:
          return 2 if opc.version >= 3.6 else 1
      else:
          return 2 if opc.version >= 3.6 else 3
docs: For a given opcode, `op`, in opcode module `opc`,
      return the size, in bytes, of an `op` instruction.
  
      This is the size of the opcode (1 byte) and any operand it has. In
      Python before version 3.6 this will be either 1 or 3 bytes.  In
      Python 3.6 or later, it is 2 bytes or a "word".