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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 set_col_width(self, col, tab, width):
 """Sets column width"""


        try:
            old_width = self.col_widths.pop((col, tab))

        except KeyError:
            old_width = None

        if width is not None:
            self.col_widths[(col, tab)] = float(width)