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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def deprecated_arg_names(arg_mapping):
 """ Decorator which marks a functions keyword arguments as deprecated. It will result in a warning being emitted when the deprecated keyword argument is used, and the function being called with the new argument. Parameters arg_mapping : dict[str, str] Mapping from deprecated argument name to current argument name. """

    def decorator(func):
        @wraps(func)
        def func_wrapper(*args, **kwargs):
            warnings.simplefilter(
                'always', DeprecationWarning)  # turn off filter
            for old, new in arg_mapping.items():
                if old in kwargs:
                    warnings.warn(
                        "Keyword argument '{0}' has been deprecated in favour "
                        "of '{1}'. '{0}' will be removed in a future version."
                        .format(old, new),
                        category=DeprecationWarning,
                        stacklevel=2,
                    )
                    val = kwargs.pop(old)
                    kwargs[new] = val
            warnings.simplefilter(
                'default', DeprecationWarning)  # reset filter
            return func(*args, **kwargs)
        return func_wrapper
    return decorator