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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 _get_fld2col_widths(self, **kws):
 """Return xlsx column widths based on default and user-specified field-value pairs."""

        fld2col_widths = self._init_fld2col_widths()
        if 'fld2col_widths' not in kws:
            return fld2col_widths
        for fld, val in kws['fld2col_widths'].items():
            fld2col_widths[fld] = val
        return fld2col_widths