Remove leading and trailing white spaces in a column's values

        :param col: name of the column
        :type col: str

        :example: ``ds.strip("mycol")``

def strip(self, col: str):
        """
        Remove leading and trailing white spaces in a column's values

        :param col: name of the column
        :type col: str

        :example: ``ds.strip("mycol")``
        """
        def remove_ws(row):
            val = str(row[col])
            if " " in val.startswith(" "):
                row[col] = val.strip()
            return row

        try:
            self.df.apply(remove_ws)
        except Exception as e:
            self.err(e, "Can not remove white space in column")
            return
        self.ok("White space removed in column values")