new_contents: def add_names(list_of_names, file):
    """
    Opens and adds a list of names to the end of a file, each on its own line
    """
    # We open a file in 'a' mode, for appending to it.
    names_file = open(file, 'a')
  
    # For each line in the list, we print that to the file. 
    # This assumes one file per line.
    for name in list_of_names:
      print >> names_file, name
  
    # Close the file so the changes are visible.
    names_file.close()
  
  
  # Exercise: make new_names customizible:
  new_names = ['John', 'Sarah', 'Taj']
  
  # Exercise: make the file name used here customizible:
  add_names(new_names, 'names.txt')
  
  
subject: Add names script