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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 unmerge(self, unmerge_area, tab):
 """Unmerges all cells in unmerge_area"""


        top, left, bottom, right = unmerge_area
        selection = Selection([(top, left)], [(bottom, right)], [], [], [])
        attr = {"merge_area": None, "locked": False}

        self._set_cell_attr(selection, tab, attr)