<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def plot_file(self, name: str=None, time: int=None) -> None: """ Plot specific time for provided datafile. If no time provided, will plot middle. :param: savefile name :param: time/data column """

        if not time:
            time = int(len(self.times) / 2)
        if not name:
            name = './img/' + self.filename + '.png'
        yhat, residuals, residual_mean, noise = self._get_fit(time)
        plt.figure()
        plt.scatter(self.domain, self.averagedata[:, time], alpha=0.2)
        plt.plot(yhat)
        plt.savefig(name)