'Fill in the answer to the problem.
args:
text: String to fill the input with.
kwargs:
input_num: If provided, fills only the input_numth field. Else, all
input fields will be filled.'

def fill_answer(self, text, input_num=None):

    fields = self.q(css='div.problem    div.capa_inputtype.textline    input')
    fields = (fields.nth(input_num) if (input_num is not None) else fields)
    fields.fill(text)
