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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 childgroup(self, field):
 """ Return children grouped regarding the grid description """

        cols = getattr(self, "cols", self.default_cols)
        width = self.num_cols / cols
        for child in field.children:
            child.width = width
        res = list(grouper(field.children, cols, fillvalue=None))
        return res