Simplifies creation of decorators

decorator.py

from functools import wraps

def decorator(wrapper):
    """Simplifies creation of decorators.
    Removes a layer of nesting (flat is better than nested).

    Note that args and kwargs are passed in as simple positional args,
    rather than unpacked *args and **kwargs. This avoids potential naming
    conflicts between kwargs defined in the wrapped function and the first
    arg of the wrapper (usually named "wrapped"). As a side effect, it
    discourages unpacking of those args, which decorators generally shouldn't
    be doing anyway.

    Example:

        @decorator
        def log_call(wrapped, args, kwargs):
            print("entering", wrapped)
            return wrapped(*args, **kwargs)

        # Instead of:

        def log_call(wrapped):
            @wraps(wrapped)
            def wrapper(*args, **kwargs):
                print("entering", wrapped)
                return wrapped(*args, **kwargs)
            return wrapper
    """
    @wraps(wrapper)
    def new_decorator(*new_decorator_args):
        # new_decorator_args will be [wrapped] for functions,
        # or [self, wrapped] for methods.
        @wraps(new_decorator_args[-1])
        def new_wrapper(*args, **kwargs):
            # See docstring for why we don't send args and kwargs unpacked.
            # In python >= 3.5, this can be simplified w/ a leading splat.
            return wrapper(*(new_decorator_args + (args, kwargs)))
        return new_wrapper
    return new_decorator