some issues of eval.py

[someonebuymelon]

usage: eval.py [-h] [--test_path TEST_PATH]
[--test_scaffolds_path TEST_SCAFFOLDS_PATH]
[--train_path TRAIN_PATH] [--ptest_path PTEST_PATH]
[--ptest_scaffolds_path PTEST_SCAFFOLDS_PATH] --gen_path
GEN_PATH [--ks KS [KS ...]] [--n_jobs N_JOBS] [--device DEVICE]
eval.py: error: the following arguments are required: --gen_path