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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 _assert_valid_start(start_int, count_int, total_int):
 """Assert that the number of objects visible to the active subject is higher than the requested start position for the slice. This ensures that it's possible to create a valid slice. """

    if total_int and start_int >= total_int:
        raise d1_common.types.exceptions.InvalidRequest(
            0,
            'Requested a non-existing slice. start={} count={} total={}'.format(
                start_int, count_int, total_int
            ),
        )