code: import matplotlib.pyplot as plt
  import matplotlib.dates as mdates
  from datetime import datetime as dt
  import pandas as pd 
  import numpy as np
  
  # Load the csv
  df1 = pd.read_csv('data/aggregate-daily-values.csv')
  df2 = pd.read_csv('data/aggregate-daily-values-covid-19.csv')
  df3 = pd.read_csv('data/aggregate-daily-values-cats.csv')
  
  time_values1 = []
  interest_values1 = []
  
  time_values2 = []
  interest_values2 = []
  
  time_values3 = []
  interest_values3 = []
  
  for i, row in df1.iterrows():
  	time_values1.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d'))) #dates
  	# time_values.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d %H:%M:%S'))) #datetime
  	interest_values1.append(row['interest'])
  
  for i, row in df2.iterrows():
  	time_values2.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d'))) #dates
  	# time_values.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d %H:%M:%S'))) #datetime
  	interest_values2.append(row['interest'])
  
  for i, row in df3.iterrows():
  	time_values3.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d'))) #dates
  	# time_values.append(mdates.date2num(dt.strptime(row['date'], '%Y-%m-%d %H:%M:%S'))) #datetime
  	interest_values3.append(row['interest'])
  
  fig, ax = plt.subplots()
  
  ax.set_title('Interest in COVID-19 (Google Trends)')
  ax.set_ylabel('Interest')
  ax.plot_date(time_values1, interest_values1, linestyle='-', marker='o', color='blue', label='Toilet Paper')
  ax.plot_date(time_values2, interest_values2, linestyle='-', marker='o', color='black', label='COVID-19')
  ax.plot_date(time_values3, interest_values3, linestyle='-', marker='o', color='red', label='Cats')
  
  
  # For data within the same day.
  #hfmt = mdates.DateFormatter('%H:%M:%S')
  #ax.set_xlabel('Time')
  
  # For larger data sets.
  hfmt = mdates.DateFormatter('%b %d %Y')
  ax.set_xlabel('Date')
  
  ax.xaxis.set_major_formatter(hfmt)
  plt.gcf().autofmt_xdate()
  plt.legend()
  plt.show()
  
apis: matplotlib.pyplot.legend pandas.read_csv matplotlib.pyplot.gcf matplotlib.dates.DateFormatter matplotlib.pyplot.subplots matplotlib.pyplot.show