code: def parse_instruction(string, location, tokens):
      
      mnemonic_str = ReilMnemonic.from_string(tokens["mnemonic"])
  
      oprnd1 = tokens["fst_operand"][0]
      oprnd2 = tokens["snd_operand"][0]
      oprnd3 = tokens["trd_operand"][0]
  
      ins_builder = ReilBuilder()
  
      return ins_builder.build(mnemonic_str, oprnd1, oprnd2, oprnd3)
docs: Parse instruction.