y 3dmx 2bc trend analysis in for a column of dataframe

1import matplotlib.pyplot as pltimport matplotlib.dates as mdatesfig, ax = plt.subplots()ax.grid(True)year = mdates.YearLocator(month=1)month = mdates.MonthLocator(interval=3)year_format = mdates.DateFormatter('%Y')month_format = mdates.DateFormatter('%m')ax.xaxis.set_minor_locator(month)ax.xaxis.grid(True, which = 'minor')ax.xaxis.set_major_locator(year)ax.xaxis.set_major_formatter(year_format)plt.plot(data_set.index, data_set['#Passengers'], c='blue')plt.plot(decomposition.trend.index, decomposition.trend, c='red')