code: @Override
      public void visitCode(Code obj) {
          try {
              stack.resetForMethodEntry(this);
              reportedType = ImmutabilityType.UNKNOWN;
              super.visitCode(obj);
          } catch (StopOpcodeParsingException e) {
              // report type is immutable
          }
      }
docs: overrides the visitor to reset the opcode stack, and reset the reported immutability of the method
  
  @param obj
  the context object of the currently parse code block