old_contents: #! /usr/bin/env python
  
  import csv
  
  def get_rows(fspec_csv):
      with open(fspec_csv) as fin:
          sheet = csv.reader(fin)
          yield from sheet
  
  
  def count_matches(census_csv, los_angeles_prospects_csv):
      census = sorted(get_rows(census_csv))
      for
  
new_contents: #! /usr/bin/env python
  
  import csv
  
  def get_rows(fspec_csv):
      with open(fspec_csv) as fin:
          sheet = csv.reader(fin)
          yield from sheet
  
  
  def count_matches(
          census_csv="/tmp/census.csv",
          los_angeles_prospects_csv="/tmp/prospects.csv"):
      count = 0
      for zipcode in get_rows(los_angeles_prospects_csv):
          census = sorted(get_rows(census_csv))
          if zipcode in census:
              count += 1
  
      return count
  
  
  if __name__ == '__main__':
      assert 60 == count_matches()
  
subject: Add (deliberately inefficient) count_matches()