Get the column change options.

def _get_column_change_options(self, fluent):
        """
        Get the column change options.
        """
        options = super(MySQLSchemaGrammar, self)._get_column_change_options(fluent)

        if fluent.type == "enum":
            options["extra"] = {
                "definition": "('{}')".format("','".join(fluent.allowed))
            }

        return options