Could not convert string to float error

[huabawa]

Traceback (most recent call last):
File "generator.py", line 200, in
main(sys.argv)
File "generator.py", line 195, in main
generate(data_fn, out_fn, N_epochs)
File "generator.py", line 141, in generate
diversity=diversity)
File "generator.py", line 93, in __generate_grammar
length = float(next_val.split(',')[1])
ValueError: could not convert string to float: