code: def replace_heroku_db(self, file_url):
          
          self.print_message("Replacing database for Heroku app '%s'" % self.args.destination_app)
  
          self.reset_heroku_database()
  
          if file_url:
              self.print_message("Restoring from URL '%s'" % file_url)
              args = [
                  "heroku",
                  "pg:backups:restore",
                  file_url,
                  "--app=%s" % self.args.destination_app,
                  "DATABASE",
                  "--confirm",
                  self.args.destination_app,
              ]
              if self.args.use_pgbackups:
                  args = [
                      "heroku",
                      "pgbackups:restore",
                      "--app=%s" % self.args.destination_app,
                      "DATABASE_URL",
                      "--confirm",
                      self.args.destination_app,
                      file_url,
                  ]
              subprocess.check_call(args)
          else:
              # TODO perhaps add support for file -> heroku by piping to pg:psql
              self.print_message("Pushing data from database '%s'" % self.databases['source']['name'])
              self.print_message("NOTE: Any postgres authentication settings you passed to paragres "
                                 "will be ignored.\nIf desired, you can export PG* variables.\n"
                                 "You will be prompted for your psql password.")
              args = [
                  "heroku",
                  "pg:push",
                  self.databases['source']['name'],
                  "DATABASE_URL",
                  "--app=%s" % self.args.destination_app,
              ]
              subprocess.check_call(args)
docs: Replace Heroku database with database from specified source.