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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 at(self, row, col):
 """Return the value at the given cell position. Args: row (int):
 zero-based row number col (int):
 zero-based column number Returns: cell value Raises: TypeError: if ``row`` or ``col`` is not an ``int`` IndexError: if the position is out of range """

        if not (isinstance(row, int) and isinstance(col, int)):
            raise TypeError(row, col)
        return self._values[row][col]