When I run the train_val.py and training from my txt file which contain country name getting error

[VinayMandal]

Size of training vocabulary = 19 Number of unique input characters: 34 Number of unique target characters: 31 Max sequence length in the training set: 11 Traceback (most recent call last): File "train_val.py", line 89, in val_tokens, maxlen, error_rate=error_rate, shuffle=False) File "/media/sf_VM/vindo_pro/deep-spell-checkr/utils.py", line 149, in transform assert(len(encoder) == len(decoder) == len(target)) AssertionError