在abaqus二次开发中出现TypeError: String Expected as dictionary Key 如何解决？

在abaqus-python的二次开发中

if len(points) == 0:
    points.append(point)
    RamAggDatas.append([ik + 1, x1, y1, z1, AMaxlen[ik][0] / 2.0])
elif interact_judgement(points,point):
    points.append(point)
    RamAggDatas.append([ik + 1, x1, y1, z1, AMaxlen[ik][0] / 2.0])
else:
    del mdb.models[Modelname].rootAssembly.features['Part-' + str(ik)]
    pass
Cumcellvolume = Cumcellvolume + cellvolume[ik][0]
if (Cumcellvolume - Targetvol) >= 0.0:
    break

TypeError: String Expected as dictionary Key

关于type报错，这个字符串作为字典键的问题是哪里出错了