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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 change_return_type(f):
 """ Converts the returned value of wrapped function to the type of the first arg or to the type specified by a kwarg key return_type's value. """

    @wraps(f)
    def wrapper(*args, **kwargs):
        if kwargs.has_key('return_type'):
            return_type = kwargs['return_type']
            kwargs.pop('return_type')
            return return_type(f(*args, **kwargs))
        elif len(args) > 0:
            return_type = type(args[0])
            return return_type(f(*args, **kwargs))
        else:
            return f(*args, **kwargs)
    return wrapper