code: def op_get_opcode_name(op_string):
      
      global OPCODE_NAMES
  
      # special case...
      if op_string == '{}:'.format(NAME_REGISTRATION):
          return 'NAME_RENEWAL'
  
      op = op_string[0]
      if op not in OPCODE_NAMES:
          raise Exception('No such operation "{}"'.format(op))
  
      return OPCODE_NAMES[op]
docs: Get the name of an opcode, given the 'op' byte sequence of the operation.