old_contents: # Configuration File with global variables
  
  # Every possible symbol that can be encrypted:
  SYMBOLS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890 !?.'
  
new_contents: """Configuration file with global variables.
  
  Mainly contains definition of every possible encryptable symbol.
  
  Attributes:
      SYMBOLS (str): Every possible symbol that can be encrypted.
  """
  # Every possible symbol that can be encrypted:
  SYMBOLS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890 !?.'
  
subject: Update Chapter01/config.py added docstring