fixed cpu __repr__ method

riscemu/CPU.py

@@ -100,5 +100,5 @@ class CPU:
         return "CPU(pc=0x{:08X}, cycle={}, instructions={})".format(
             self.pc,
             self.cycle,
-            " ".join(s.name for s in self.sets)
+            " ".join(s.name for s in self.instruction_sets)
         )

riscemu/instructions/InstructionSet.py

@@ -10,6 +10,7 @@ class InstructionSet(ABC):
     """
 
     def __init__(self, cpu: 'CPU'):
+        self.name = self.__class__.__name__
         self.cpu = cpu
         self.mmu = cpu.mmu
         self.regs = cpu.regs