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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 generate_table(self):
 """ Generates the GSO lookup table for the DataFRame Returns ------- gso_table : OrderedDict Ordered dictionary using the string found as keys and their lookup position (v,o) as values gso_df : DataFrame DataFrame where strl columns have been converted to (v,o) values Notes ----- Modifies the DataFrame in-place. The DataFrame returned encodes the (v,o) values as uint64s. The encoding depends on teh dta version, and can be expressed as enc = v + o * 2 ** (o_size * 8) so that v is stored in the lower bits and o is in the upper bits. o_size is * 117: 4 * 118: 6 * 119: 5 """


        gso_table = self._gso_table
        gso_df = self.df
        columns = list(gso_df.columns)
        selected = gso_df[self.columns]
        col_index = [(col, columns.index(col)) for col in self.columns]
        keys = np.empty(selected.shape, dtype=np.uint64)
        for o, (idx, row) in enumerate(selected.iterrows()):
            for j, (col, v) in enumerate(col_index):
                val = row[col]
                # Allow columns with mixed str and None (GH 23633)
                val = '' if val is None else val
                key = gso_table.get(val, None)
                if key is None:
                    # Stata prefers human numbers
                    key = (v + 1, o + 1)
                    gso_table[val] = key
                keys[o, j] = self._convert_key(key)
        for i, col in enumerate(self.columns):
            gso_df[col] = keys[:, i]

        return gso_table, gso_df