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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 serialize(self, serialize_cell=None):
 """Returns a list of all rows, with serialize_cell or self.get_cell_value called on the cells of each. """

    if serialize_cell is None:
      serialize_cell = self.get_cell_value
    return [[serialize_cell(cell) for cell in row] for row in self.rows]