Error while plotting time series
import pandas as pd
df3 = pd.read_csv('https://raw.githubusercontent.com/nytimes/covid-19-data/master/us.csv')
# For column names, replace space with an underscore and also change the case to lower
df3 = df3.columns.str.replace(' ', '_').str.lower()
# Get a time series to plot
ts = pd.Series(df3['deaths'].values, index=df3['date'])
ts.plot()