notation5.lean:3:0: error: invalid token `((`, it starts with '('
notation5.lean:5:0: error: invalid token `(`, it starts with '('
notation5.lean:7:0: error: invalid token `))`, it ends with ')'
notation5.lean:9:0: error: invalid token `,,`, it contains reserved character `,`
notation5.lean:11:0: error: invalid token `,`, it contains reserved character `,`