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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 boardToString(self, margins=None):
 """ return a string representation of the current board. """

        if margins is None:
            margins = {}

        b = self.board
        rg = range(b.size())
        left = ' '*margins.get('left', 0)
        s = '\n'.join(
            [left + ' '.join([self.getCellStr(x, y) for x in rg]) for y in rg])
        return s