def fk(self, primary_table=None, foreign_table=None, owner=None, schema=None):
        cur = self.begin()
        if primary_table and foreign_table:
            cur.foreignkeys(schema, owner, primary_table, schema, owner, foreign_table)
        elif primary_table:
            cur.foreignkeys(schema, owner, primary_table, schema, owner, None)
        elif foreign_table:
            cur.foreignkeys(schema, owner, None, schema, owner, foreign_table)
        self.commit(cur)
        self.display()
display the table's foreign keys
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/dbexts.py/dbexts.fk