def p_ex_list(self, p):
if p[<NUM_LIT:2>] is None:<EOL><INDENT>p[<NUM_LIT:0>] = []<EOL><DEDENT>else:<EOL><INDENT>p[<NUM_LIT:0>] = p[<NUM_LIT:2>]<EOL><DEDENT>
ex_list : LBRACKET ex_list_items RBRACKET
                   | LBRACKET empty RBRACKET