<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def final_data_transform_factory(alg, sep, pre_sep):
 """ Create a function to transform a tuple. Parameters alg : ns enum Indicate how to format the *str*. sep : str Separator that was passed to *parse_string_factory*. pre_sep : str String separator to insert at the at the front of the return tuple in the case that the first element is *sep*. Returns ------- func : callable A function to be used as the *final_transform* argument to *parse_string_factory*. See Also -------- parse_string_factory """

    if alg & ns.UNGROUPLETTERS and alg & ns.LOCALEALPHA:
        swap = alg & NS_DUMB and alg & ns.LOWERCASEFIRST
        transform = methodcaller("swapcase") if swap else _no_op

        def func(split_val, val, _transform=transform, _sep=sep, _pre_sep=pre_sep):
            """
            Return a tuple with the first character of the first element
            of the return value as the first element, and the return value
            as the second element. This will be used to perform gross sorting
            by the first letter.
            """
            split_val = tuple(split_val)
            if not split_val:
                return (), ()
            elif split_val[0] == _sep:
                return (_pre_sep,), split_val
            else:
                return (_transform(val[0]),), split_val

        return func
    else:
        return lambda split_val, val: tuple(split_val)