code: def get_input_from_submission(self, submission, only_input=False):
          
          inp = bson.BSON.decode(self._gridfs.get(submission['input']).read())
          if only_input:
              return inp
          else:
              submission["input"] = inp
              return submission
docs: Get the input of a submission. If only_input is False, returns the full submissions with a dictionnary object at the key "input".
              Else, returns only the dictionnary.