How to plot date series in matplotlib?

[StrybolData]

I used the following code to format my series into timestamps, but I would like to now visualise it with pyplot. I based the format on the python datetime object, so to plot time with matplotlib I converted my column into a python datetime and then to the pyplot format...

Datetime format

spreads['Created at'] = pd.to_datetime(timedata).apply(lambda x:x.strftime('%H:%M:%S'))

outcome : 07:20:00

Next step pyplot format

> import matplotlib.pyplot as plt import random
 
 x = matplotlib.dates.date2num(spreads['Created at']) y =
 y = [i+random.gauss(0,1) for i,_ in enumerate(x)]
 
 plt.plot(x,y)

AttributeError: 'str' object has no attribute 'toordinal'

Could somebody explain me what is wrong with my code?