import matplotlib
matplotlib.use('Qt5Agg')
import pandas as pd
import matplotlib.pyplot as mpp
import matplotlib.patches as patches
import matplotlib.dates as mdates
import datetime
import numpy as np

data=dict()
data['timestamps'] = [datetime.datetime(2018,2,1)+datetime.timedelta(days=x) for x in range(0,10)]

data['Requests'] = np.array([5,4,7,3,5,4,5,6,7,8])

fig,ax = mpp.subplots()
ax.plot(data['timestamps'], data['Requests'])
print(mdates.date2num(datetime.datetime(2018,2,2,0,0,0)))
ax.add_patch(patches.Rectangle(
    (mdates.date2num(datetime.datetime(2018,2,2,0,0,0)), ax.get_ylim()[0]),
    2., ax.get_ylim()[1]))
mpp.show()

import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle
from datetime import datetime, timedelta

data = pd.DataFrame({
            "Timestamp":pd.date_range(start=datetime(2018,1,30,0,0,0),
                                      end=datetime(2018,2,8,0,0,0),freq='d'),
            "Requests":[5,4,7,3,5,4,5,6,7,8]})

fig, ax = plt.subplots()
ax.plot(data.Timestamp, data.Requests)

xy = datetime(2018,2,2,0,0,0), ax.get_ylim()[0]
w, h = timedelta(days=2), ax.get_ylim()[1] - ax.get_ylim()[0]
ax.add_patch(Rectangle(xy, w, h))

fig.show()