Class decorators using __call__ function

Question

I'm using sqlachemy to connect to MYSQL and need to close connection after each query is executed.

Planning to use class decorators to accomplish this. Here is my brief code.

I get this error:
TypeError: __call__() missing 1 required positional argument: 'args'

class Connection(object):

    class close_sqlalchemy_connection(object):
        def __init__(self, f):
            print("inside myDecorator.__init__()")
            self.f = f

        def __call__(self, args):
            print("inside myDecorator.__call__()", *args )
            self.f(args)
            print("function decorted")

    def __init__(self):
        self.mysql_engine = 'mysql_engine' # this will be mysql sqlalchemy connection

    @close_sqlalchemy_connection
    def execute_query(self):
        print('execute_query')


i = Connection()
i.execute_query()

Answer 1

Try using a decorator function, much easier if you don't need additional parameters on setup such as

@decorator(*params)
def method(...):

Here's an example:

from functools import wraps 
class Connection(object):

    def close_sqlalchemy_connection(f):
        @wraps (f)
        def inner(*args, **kwargs):
            # args[0] is instance itself, if you want to do things with it
            return f(*args, **kwargs)
        return inner 


    def __init__(self):
        self.mysql_engine = 'mysql_engine' # this will be mysql sqlalchemy connection

    @close_sqlalchemy_connection
    def execute_query(self):
        print('execute_query')


i = Connection()
i.execute_query()