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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 _simple_blockify(tuples, dtype):
 """ return a single array of a block that has a single dtype; if dtype is not None, coerce to this dtype """

    values, placement = _stack_arrays(tuples, dtype)

    # CHECK DTYPE?
    if dtype is not None and values.dtype != dtype:  # pragma: no cover
        values = values.astype(dtype)

    block = make_block(values, placement=placement)
    return [block]