docs: def run(self):
          """ Replace a database with the data from the specified source. """
          self.print_message("\nBeginning database replacement process.\n")
  
          if self.args.source_settings:
              settings = self.parse_db_settings(self.args.source_settings)
              self.initialize_db_args(settings, 'source')
  
          if self.args.settings:
              settings = self.parse_db_settings(self.args.settings)
              self.initialize_db_args(settings, 'destination')
  
          if self.args.capture:
              self.capture_heroku_database()
  
          file_url = self.args.url
          if self.args.source_app:
              self.print_message("Sourcing data from backup for Heroku app '%s'"
                                 % self.args.source_app)
              file_url = self.get_file_url_for_heroku_app(self.args.source_app)
  
          if self.args.destination_app:
              self.replace_heroku_db(file_url)
          elif self.databases['destination']['name']:
              self.replace_postgres_db(file_url)
  
          self.print_message("\nDone.\n\nDon't forget to update the Django Site entry if necessary!")