code: def do_db(self, arg):
          
          if arg['get_config']:
              self.db_get_config()
          elif arg['use_local_file']:
              self.db_use_local_file(arg, filename=arg['<filename>'])
          elif arg['use_aws_instance']:
              self.db_use_aws_instance(arg['<instance_id>'], arg)
          elif arg['aws_list_regions']:
              self.db_aws_list_regions()
          elif arg['aws_get_region']:
              self.db_aws_get_region()
          elif arg['aws_set_region']:
              self.db_aws_set_region(arg['<region_name>'])
          elif arg['aws_list_instances']:
              self.db_aws_list_instances()
          elif arg['aws_create_instance']:
              self.db_create_aws_db_instance(arg['<instance_id>'], arg['<size>'],
                                             arg['<username>'],
                                             arg['<password>'], arg['<dbname>'])
          elif arg['aws_delete_instance']:
              self.db_aws_delete_instance(arg['<instance_id>'])
          else:
              self.help_db()
docs: Usage:
            db get_config
            db use_local_file [<filename>]
            db use_aws_instance [<instance_id>]
            db aws_list_regions
            db aws_get_region
            db aws_set_region [<region_name>]
            db aws_list_instances
            db aws_create_instance [<instance_id> <size> <username> <password>
                                    <dbname>]
            db aws_delete_instance [<instance_id>]
            db help