The double_args decorator is a decorator that takes a function as an argument and returns a new function that doubles the arguments of the original function. Here's an example implementation of the double_args decorator:

def double_args(func):
    def wrapper(*args, **kwargs):
        # Double the positional arguments
        new_args = [2 * arg for arg in args]
        # Double the keyword arguments
        new_kwargs = {k: 2 * v for k, v in kwargs.items()}
        # Call the original function with the doubled arguments
        return func(*new_args, **new_kwargs)
    return wrapper

The double_args decorator takes a function as an argument and returns a new function wrapper. The wrapper function takes any number of positional and keyword arguments using the *args and **kwargs syntax, respectively. It doubles the positional arguments and keyword arguments by creating new lists and dictionaries using a list comprehension and dictionary comprehension, respectively. Finally, it calls the original function with the doubled arguments using the func(*new_args, **new_kwargs) syntax.

Here's an example of using the double_args decorator to double the arguments of a function:

@double_args
def add_numbers(a, b, c=0):
    return a + b + c
 
result = add_numbers(1, 2, c=3)
print(result)  # Output: 12 (doubled arguments: 2, 4, 6)

In the above example, the add_numbers function is decorated with the double_args decorator using the @ syntax. When add_numbers is called with arguments 1, 2, and c=3, the double_args decorator doubles the arguments and calls the original add_numbers function with the doubled arguments. The result is 12, which is the sum of the doubled arguments.

Note that the double_args decorator is just one example of a decorator, and decorators can be used to implement a wide variety of functionality beyond just doubling arguments.