old_contents: """ Chapter 3 Zipf City Population plot by Krugman using Wikipedia data
  >>> df = pd.read_html('https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population', header=0)[3]
  >>> rankpop = df[[df.columns[0], df.columns[3]]]
  >>> axes = rankpop.plot(style='o', logx=True, logy=True)
  >>> xlabel = plt.xlabel('US City Rank in Population')
  >>> ylabel = plt.ylabel('US City Population')
  >>> title plt.title('Counting People in Cities Like Counting Words in Documents')
  >>> plt.tight_layout()
  >>> plt.show()
  """
  import pandas as pd
  
  df = pd.read_html('https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population', header=0)[3]
  rankpop = df[[df.columns[0], df.columns[3]]]
  axes = rankpop.plot(style='o', logx=True, logy=True)
  xlabel = plt.xlabel('US City Rank in Population')
  ylabel = plt.ylabel('US City Population')
  title plt.title('Counting People in Cities Like Counting Words in Documents')
  plt.tight_layout()
  plt.show()
new_contents: """ Chapter 3 Zipf City Population plot by Krugman using Wikipedia data
  >>> df = pd.read_html('https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population', header=0)[3]
  >>> rankpop = df[[df.columns[0], df.columns[3]]]
  >>> axes = rankpop.plot(style='o', logx=True, logy=True)
  >>> xlabel = plt.xlabel('US City Rank in Population')
  >>> ylabel = plt.ylabel('US City Population')
  >>> plt.title('Counting People in Cities Like Counting Words in Documents')
  >>> plt.tight_layout()
  >>> plt.show()
  """
  import pandas as pd
  import seaborn
  from matplotlib import pyplot as plt
  
  df = pd.read_html('https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population', header=0)[3]
  rankpop = df[[df.columns[0], df.columns[3]]]
  axes = rankpop.plot(style='o', logx=True, logy=True)
  xlabel = plt.xlabel('US City Rank in Population')
  ylabel = plt.ylabel('US City Population')
  plt.title('Counting People in Cities Like Counting Words in Documents')
  plt.tight_layout()
  plt.show()
subject: fix plot