JSONDecode error while using Google colab

Question

I am trying to use google colab for a project of mine but been stuck at this error since a long time. Any help would be highly appreciated. Here is my code snippet:

gpt2_simple.finetune(
    sess,
    dataset='input.txt',
    model_name='1.5B',
    steps=1000,
    restore_from='fresh',
    run_name='run1',
    print_every=10,
    sample_every=200,
    save_every=500
)

And the error:

JSONDecodeError                           Traceback (most recent call last)
<ipython-input-23-97af274a4eb8> in <module>()
      7               print_every=10,
      8               sample_every=200,
----> 9               save_every=500)

5 frames
/usr/lib/python3.6/json/decoder.py in raw_decode(self, s, idx)
    355             obj, end = self.scan_once(s, idx)
    356         except StopIteration as err:
--> 357             raise JSONDecodeError("Expecting value", s, err.value) from None
    358         return obj, end

JSONDecodeError: Expecting value: line 1 column 1 (char 0)