code: def moving_frequency(self, data_frame):
          
          f = []
          for i in range(0, (data_frame.td[-1].astype('int') - self.window)):
              f.append(sum(data_frame.action_type[(data_frame.td >= i) & (data_frame.td < (i + self.window))] == 1) /
                       float(self.window))
  
          diff_mov_freq = (np.array(f[1:-1]) - np.array(f[0:-2])) / np.array(f[0:-2])
  
          duration = math.ceil(data_frame.td[-1])
  
          return diff_mov_freq, duration
docs: This method returns moving frequency
  
              :param data_frame: the data frame
              :type data_frame: pandas.DataFrame
              :return diff_mov_freq: frequency
              :rtype diff_mov_freq: float