def _simple_blockify(tuples, dtype):
values, placement = _stack_arrays(tuples, dtype)<EOL>if dtype is not None and values.dtype != dtype:  <EOL><INDENT>values = values.astype(dtype)<EOL><DEDENT>block = make_block(values, placement=placement)<EOL>return [block]<EOL>
return a single array of a block that has a single dtype; if dtype is
    not None, coerce to this dtype